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T H E H Y D R O E L E C T R I C P O W E R P L A N T O F P O N T V E N T O U X - S U S A
w w w . i r e n e n e r g i a . i t
Iren Energia is the company in the Iren Group whose core
businesses are the production and distribution of electri-
city, the production and distribution of thermal energy for
district heating and the provision of technological services
Iren Energia constantly pursues its objectives, which are qua-
lity, reliability, sustainable development, energy efficiency
and a close relationship with the areas in which it operates.
The hydroelectric power plant of Pont Ventoux-Susa
has an installed capacity of 150 MW and uses water
from the river Dora Riparia and its tributary Rio Clarea.
The water is conveyed along an off-take canal in a tun-
nel to the Clarea Valley reservoir, the starting point of the
pressure tunnel leading to the forced pipeline, which, in
turn, leads to the plant in the cavern.
Downstream of the plant the water is returned to the Gor-
ge della Dora reservoir and may be pumped back at night-
time to the Clarea Valley reservoir, so that it can be reused
to produce electricity during the daytime.
MAIN PLANT CHARACTERISTICS
Pont Ventoux intake works Altitude considered normal 1,046.30 m a.s.l.
Clarea Valley reservoir Altitude considered normal 1,030.50 m a.s.l.
Capacity 561,000 m3
Gorge reservoir Altitude considered normal 531.20 m a.s.l.
Capacity 442,000 m3
General information Subtended catchment basins 536 km2
Maximum net head 502.92 m
Efficient power 150 MW
Mean energy coefficient 1.23 kWh/m3
Mean power output per year of over 350 GWh
Iren Energia S.p.A.Corso Svizzera, 9510143 Torino - ItalyTel. +39 011 5549 111Fax +39 011 53 83 13
Cutaway of plant in cavern (three-component unit)
The Hydroelectric Power Plant of Pont Ventoux-Susa oc
tobe
r 20
13
T H E H Y D R O E L E C T R I C P O W E R P L A N T O F P O N T V E N T O U X - S U S A
w w w . i r e n e n e r g i a . i t
Iren Energia is the company in the Iren Group whose core
businesses are the production and distribution of electri-
city, the production and distribution of thermal energy for
district heating and the provision of technological services
Iren Energia constantly pursues its objectives, which are qua-
lity, reliability, sustainable development, energy efficiency
and a close relationship with the areas in which it operates.
The hydroelectric power plant of Pont Ventoux-Susa
has an installed capacity of 150 MW and uses water
from the river Dora Riparia and its tributary Rio Clarea.
The water is conveyed along an off-take canal in a tun-
nel to the Clarea Valley reservoir, the starting point of the
pressure tunnel leading to the forced pipeline, which, in
turn, leads to the plant in the cavern.
Downstream of the plant the water is returned to the Gor-
ge della Dora reservoir and may be pumped back at night-
time to the Clarea Valley reservoir, so that it can be reused
to produce electricity during the daytime.
MAIN PLANT CHARACTERISTICS
Pont Ventoux intake works Altitude considered normal 1,046.30 m a.s.l.
Clarea Valley reservoir Altitude considered normal 1,030.50 m a.s.l.
Capacity 561,000 m3
Gorge reservoir Altitude considered normal 531.20 m a.s.l.
Capacity 442,000 m3
General information Subtended catchment basins 536 km2
Maximum net head 502.92 m
Efficient power 150 MW
Mean energy coefficient 1.23 kWh/m3
Mean power output per year of over 350 GWh
Iren Energia S.p.A.Corso Svizzera, 9510143 Torino - ItalyTel. +39 011 5549 111Fax +39 011 53 83 13
Cutaway of plant in cavern (three-component unit)
The Hydroelectric Power Plant of Pont Ventoux-Susa oc
tobe
r 20
13
T H E H Y D R O E L E C T R I C P O W E R P L A N T O F P O N T V E N T O U X - S U S A
w w w . i r e n e n e r g i a . i t
Iren Energia is the company in the Iren Group whose core
businesses are the production and distribution of electri-
city, the production and distribution of thermal energy for
district heating and the provision of technological services
Iren Energia constantly pursues its objectives, which are qua-
lity, reliability, sustainable development, energy efficiency
and a close relationship with the areas in which it operates.
The hydroelectric power plant of Pont Ventoux-Susa
has an installed capacity of 150 MW and uses water
from the river Dora Riparia and its tributary Rio Clarea.
The water is conveyed along an off-take canal in a tun-
nel to the Clarea Valley reservoir, the starting point of the
pressure tunnel leading to the forced pipeline, which, in
turn, leads to the plant in the cavern.
Downstream of the plant the water is returned to the Gor-
ge della Dora reservoir and may be pumped back at night-
time to the Clarea Valley reservoir, so that it can be reused
to produce electricity during the daytime.
MAIN PLANT CHARACTERISTICS
Pont Ventoux intake works Altitude considered normal 1,046.30 m a.s.l.
Clarea Valley reservoir Altitude considered normal 1,030.50 m a.s.l.
Capacity 561,000 m3
Gorge reservoir Altitude considered normal 531.20 m a.s.l.
Capacity 442,000 m3
General information Subtended catchment basins 536 km2
Maximum net head 502.92 m
Efficient power 150 MW
Mean energy coefficient 1.23 kWh/m3
Mean power output per year of over 350 GWh
Iren Energia S.p.A.Corso Svizzera, 9510143 Torino - ItalyTel. +39 011 5549 111Fax +39 011 53 83 13
Cutaway of plant in cavern (three-component unit)
The Hydroelectric Power Plant of Pont Ventoux-Susa oc
tobe
r 20
13
Pont Ventoux-Susa plant
Salbertrand-Chiomonte and Chiomonte-Susa plants
In Clarea Valley, on the right side of the
valley outside the bed of the Clarea tri-
butary, a daily regulation reservoir has
been built with a net regulation volume
of 571,233 m3, which corresponds to a
maximum regulation level of 1,030.50
m a.s.l. The total length of the crest of
the reservoir is 852 m.
The reservoir was constructed by cre-
ating an artificial bed in the Clarea tri-
butary running alongside the reservoir.
The design solution adopted maintains
the surface flow of the Clarea tributa-
ry continuous without its water mixing
with the water in the river Dora Riparia
contained in the reservoir.
This was done to safeguard the flu-
vial ecosystem of the Clarea tributary
downstream of the regulation reservoir.
All the hydraulic works necessary for the
supply of the reservoir, diversion and di-
scharge of the water were built under-
ground, on the rocky right side of the
valley. The discharge works were tested
by hydraulic physical modelling.
A pressure tunnel with a circular cross
section dug with a TBM, 4.3 km long and
with a final diameter of 4.05 m, sized for
a maximum flow rate through the tur-
bine of 34 m3/s, links the regulation re-
servoir of Clarea Valley to the upstream
piezometric well. The latter consists of a
cylindrical shaft with a height of about
80 m carved into the solid rock.
The piezometric well is the starting
point of the forced pipeline, which is
also entirely carved into the rock and
consists of a metal pipeline 1,320 m
long with a variable diameter (3.50 –
3.20 – 2.80 m).
The Pont Ventoux-Susa run-of-river plant
is regulated on a daily basis and takes
water mainly from the river Dora Ripa-
ria between Pont Ventoux (municipality
of Oulx) and Susa but also from the left
tributary, Rio Clarea.
The main diversion works on the river
Dora, situated at Pont Ventoux, con-
sist of a barrier dam including a fish
ladder, intake works and a moderator
canal on the left bank that houses the
gravel and sand removers.
The altitude to which the reservoir is
normally regulated upstream of the
barrier is 1,046.30 m a.s.l.
The design of the hydraulic works
in the river bed, including the dikes
upstream and downstream of the bar-
rier was tested by physical modelling.
A minimum instantaneous release
(minimum vital flow) from the bar-
rier is guaranteed to preserve aquatic
life in the river before other tributari-
es flow into it.
The water from the river Dora Riparia
(mean diverted flow rate 9.51 m3/s)
is conveyed into an off-take canal in
a free-surface tunnel, sized for a ma-
ximum flow rate of 33 m3/s.
The canal runs on the left side of the
river Dora Riparia for about 14 km to
the Clarea Valley reservoir.
The electric power plant was built in an
underground cavern with an excavation
volume of about 35.000 m3.
The machine room level is situated at
495.00 m a.s.l. and is accessible from
the mouth of the cavern situated at a
height of 575.00 m a.s.l., on the Susa-
Venaus road, through a large tunnel su-
itable for the transit of lorries and about
1,170 m long.
The plant is also equipped with an esca-
pe tunnel about 460 m long. The tran-
sformers are installed in underground ca-
verns independent of the machine room.
The plant in the cavern houses the
hydraulic and electrical production ma-
chinery: a two-component unit (Fran-
cis turbine and generator) and a th-
ree-component unit (Francis turbine,
generator and pump), both with a ver-
tical axis and an overall efficient power
of 150 MW.
The pump, which has a maximum ca-
pacity of about 13 m3/s, transfers wa-
ter from the Gorge reservoir of the ri-
ver Dora Riparia to the regulation Clarea
Valley reservoir.
In this way, the water is made available
again in the Clarea Valley reservoir, thus
ensuring a significant additional pro-
duction of electricity for use during the
daytime when the demand is higher,
thus optimizing the use of the amount
of water available.
The high-voltage connection with the
national transmission grid is made at
the Terna transformer station in Ve-
naus by means of underground cables
to the armoured electric power plant
situated at the mouth of the tunnel for
access to the plant in the cavern.
Downstream of the plant is situated
the tunnel pressure return canal, which
is about 1.6 km long and leads into the
bed of the river Dora Riparia upstream
of the town of Susa. In order to ensu-
re the necessary demodulation of the
flows and pump storage, a concrete
arch-gravity dam was built to form a
reservoir at the gorge of the river Dora.
The body of the dam, which has a vo-
lume of about 48.000 m3, reaches a
maximum height above the river bed
of about 30 m, and has a crest about
90 m long. The net storage volume
at its maximum regulation height of
531.20 m a.s.l. is 442,200 m3.
The entire barrier permits overflowing
via four overflow thresholds that con-
verge towards a damping reservoir
downstream of the dam.
A concrete cofferdam was built im-
mediately upstream of the dam to al-
low dam construction and subsequent
maintenance work to be carried out.
The water diverted and used is retur-
ned to the river Dora Riparia down-
stream of the Gorge dam: in part
through a regulation valve situated on
the body of the dam, which ensures a
minimum vital flow and in part throu-
gh a demodulator tunnel with a circu-
lar cross section, which branches off
from the pressure return tunnel and
conveys the water to a point about
700 m downstream of the dam.
The Plant of
Pont Ventoux-Susa
Pont Ventoux-Susa plant
Salbertrand-Chiomonte and Chiomonte-Susa plants
In Clarea Valley, on the right side of the
valley outside the bed of the Clarea tri-
butary, a daily regulation reservoir has
been built with a net regulation volume
of 571,233 m3, which corresponds to a
maximum regulation level of 1,030.50
m a.s.l. The total length of the crest of
the reservoir is 852 m.
The reservoir was constructed by cre-
ating an artificial bed in the Clarea tri-
butary running alongside the reservoir.
The design solution adopted maintains
the surface flow of the Clarea tributa-
ry continuous without its water mixing
with the water in the river Dora Riparia
contained in the reservoir.
This was done to safeguard the flu-
vial ecosystem of the Clarea tributary
downstream of the regulation reservoir.
All the hydraulic works necessary for the
supply of the reservoir, diversion and di-
scharge of the water were built under-
ground, on the rocky right side of the
valley. The discharge works were tested
by hydraulic physical modelling.
A pressure tunnel with a circular cross
section dug with a TBM, 4.3 km long and
with a final diameter of 4.05 m, sized for
a maximum flow rate through the tur-
bine of 34 m3/s, links the regulation re-
servoir of Clarea Valley to the upstream
piezometric well. The latter consists of a
cylindrical shaft with a height of about
80 m carved into the solid rock.
The piezometric well is the starting
point of the forced pipeline, which is
also entirely carved into the rock and
consists of a metal pipeline 1,320 m
long with a variable diameter (3.50 –
3.20 – 2.80 m).
The Pont Ventoux-Susa run-of-river plant
is regulated on a daily basis and takes
water mainly from the river Dora Ripa-
ria between Pont Ventoux (municipality
of Oulx) and Susa but also from the left
tributary, Rio Clarea.
The main diversion works on the river
Dora, situated at Pont Ventoux, con-
sist of a barrier dam including a fish
ladder, intake works and a moderator
canal on the left bank that houses the
gravel and sand removers.
The altitude to which the reservoir is
normally regulated upstream of the
barrier is 1,046.30 m a.s.l.
The design of the hydraulic works
in the river bed, including the dikes
upstream and downstream of the bar-
rier was tested by physical modelling.
A minimum instantaneous release
(minimum vital flow) from the bar-
rier is guaranteed to preserve aquatic
life in the river before other tributari-
es flow into it.
The water from the river Dora Riparia
(mean diverted flow rate 9.51 m3/s)
is conveyed into an off-take canal in
a free-surface tunnel, sized for a ma-
ximum flow rate of 33 m3/s.
The canal runs on the left side of the
river Dora Riparia for about 14 km to
the Clarea Valley reservoir.
The electric power plant was built in an
underground cavern with an excavation
volume of about 35.000 m3.
The machine room level is situated at
495.00 m a.s.l. and is accessible from
the mouth of the cavern situated at a
height of 575.00 m a.s.l., on the Susa-
Venaus road, through a large tunnel su-
itable for the transit of lorries and about
1,170 m long.
The plant is also equipped with an esca-
pe tunnel about 460 m long. The tran-
sformers are installed in underground ca-
verns independent of the machine room.
The plant in the cavern houses the
hydraulic and electrical production ma-
chinery: a two-component unit (Fran-
cis turbine and generator) and a th-
ree-component unit (Francis turbine,
generator and pump), both with a ver-
tical axis and an overall efficient power
of 150 MW.
The pump, which has a maximum ca-
pacity of about 13 m3/s, transfers wa-
ter from the Gorge reservoir of the ri-
ver Dora Riparia to the regulation Clarea
Valley reservoir.
In this way, the water is made available
again in the Clarea Valley reservoir, thus
ensuring a significant additional pro-
duction of electricity for use during the
daytime when the demand is higher,
thus optimizing the use of the amount
of water available.
The high-voltage connection with the
national transmission grid is made at
the Terna transformer station in Ve-
naus by means of underground cables
to the armoured electric power plant
situated at the mouth of the tunnel for
access to the plant in the cavern.
Downstream of the plant is situated
the tunnel pressure return canal, which
is about 1.6 km long and leads into the
bed of the river Dora Riparia upstream
of the town of Susa. In order to ensu-
re the necessary demodulation of the
flows and pump storage, a concrete
arch-gravity dam was built to form a
reservoir at the gorge of the river Dora.
The body of the dam, which has a vo-
lume of about 48.000 m3, reaches a
maximum height above the river bed
of about 30 m, and has a crest about
90 m long. The net storage volume
at its maximum regulation height of
531.20 m a.s.l. is 442,200 m3.
The entire barrier permits overflowing
via four overflow thresholds that con-
verge towards a damping reservoir
downstream of the dam.
A concrete cofferdam was built im-
mediately upstream of the dam to al-
low dam construction and subsequent
maintenance work to be carried out.
The water diverted and used is retur-
ned to the river Dora Riparia down-
stream of the Gorge dam: in part
through a regulation valve situated on
the body of the dam, which ensures a
minimum vital flow and in part throu-
gh a demodulator tunnel with a circu-
lar cross section, which branches off
from the pressure return tunnel and
conveys the water to a point about
700 m downstream of the dam.
The Plant of
Pont Ventoux-Susa
Pont Ventoux-Susa plant
Salbertrand-Chiomonte and Chiomonte-Susa plants
In Clarea Valley, on the right side of the
valley outside the bed of the Clarea tri-
butary, a daily regulation reservoir has
been built with a net regulation volume
of 571,233 m3, which corresponds to a
maximum regulation level of 1,030.50
m a.s.l. The total length of the crest of
the reservoir is 852 m.
The reservoir was constructed by cre-
ating an artificial bed in the Clarea tri-
butary running alongside the reservoir.
The design solution adopted maintains
the surface flow of the Clarea tributa-
ry continuous without its water mixing
with the water in the river Dora Riparia
contained in the reservoir.
This was done to safeguard the flu-
vial ecosystem of the Clarea tributary
downstream of the regulation reservoir.
All the hydraulic works necessary for the
supply of the reservoir, diversion and di-
scharge of the water were built under-
ground, on the rocky right side of the
valley. The discharge works were tested
by hydraulic physical modelling.
A pressure tunnel with a circular cross
section dug with a TBM, 4.3 km long and
with a final diameter of 4.05 m, sized for
a maximum flow rate through the tur-
bine of 34 m3/s, links the regulation re-
servoir of Clarea Valley to the upstream
piezometric well. The latter consists of a
cylindrical shaft with a height of about
80 m carved into the solid rock.
The piezometric well is the starting
point of the forced pipeline, which is
also entirely carved into the rock and
consists of a metal pipeline 1,320 m
long with a variable diameter (3.50 –
3.20 – 2.80 m).
The Pont Ventoux-Susa run-of-river plant
is regulated on a daily basis and takes
water mainly from the river Dora Ripa-
ria between Pont Ventoux (municipality
of Oulx) and Susa but also from the left
tributary, Rio Clarea.
The main diversion works on the river
Dora, situated at Pont Ventoux, con-
sist of a barrier dam including a fish
ladder, intake works and a moderator
canal on the left bank that houses the
gravel and sand removers.
The altitude to which the reservoir is
normally regulated upstream of the
barrier is 1,046.30 m a.s.l.
The design of the hydraulic works
in the river bed, including the dikes
upstream and downstream of the bar-
rier was tested by physical modelling.
A minimum instantaneous release
(minimum vital flow) from the bar-
rier is guaranteed to preserve aquatic
life in the river before other tributari-
es flow into it.
The water from the river Dora Riparia
(mean diverted flow rate 9.51 m3/s)
is conveyed into an off-take canal in
a free-surface tunnel, sized for a ma-
ximum flow rate of 33 m3/s.
The canal runs on the left side of the
river Dora Riparia for about 14 km to
the Clarea Valley reservoir.
The electric power plant was built in an
underground cavern with an excavation
volume of about 35.000 m3.
The machine room level is situated at
495.00 m a.s.l. and is accessible from
the mouth of the cavern situated at a
height of 575.00 m a.s.l., on the Susa-
Venaus road, through a large tunnel su-
itable for the transit of lorries and about
1,170 m long.
The plant is also equipped with an esca-
pe tunnel about 460 m long. The tran-
sformers are installed in underground ca-
verns independent of the machine room.
The plant in the cavern houses the
hydraulic and electrical production ma-
chinery: a two-component unit (Fran-
cis turbine and generator) and a th-
ree-component unit (Francis turbine,
generator and pump), both with a ver-
tical axis and an overall efficient power
of 150 MW.
The pump, which has a maximum ca-
pacity of about 13 m3/s, transfers wa-
ter from the Gorge reservoir of the ri-
ver Dora Riparia to the regulation Clarea
Valley reservoir.
In this way, the water is made available
again in the Clarea Valley reservoir, thus
ensuring a significant additional pro-
duction of electricity for use during the
daytime when the demand is higher,
thus optimizing the use of the amount
of water available.
The high-voltage connection with the
national transmission grid is made at
the Terna transformer station in Ve-
naus by means of underground cables
to the armoured electric power plant
situated at the mouth of the tunnel for
access to the plant in the cavern.
Downstream of the plant is situated
the tunnel pressure return canal, which
is about 1.6 km long and leads into the
bed of the river Dora Riparia upstream
of the town of Susa. In order to ensu-
re the necessary demodulation of the
flows and pump storage, a concrete
arch-gravity dam was built to form a
reservoir at the gorge of the river Dora.
The body of the dam, which has a vo-
lume of about 48.000 m3, reaches a
maximum height above the river bed
of about 30 m, and has a crest about
90 m long. The net storage volume
at its maximum regulation height of
531.20 m a.s.l. is 442,200 m3.
The entire barrier permits overflowing
via four overflow thresholds that con-
verge towards a damping reservoir
downstream of the dam.
A concrete cofferdam was built im-
mediately upstream of the dam to al-
low dam construction and subsequent
maintenance work to be carried out.
The water diverted and used is retur-
ned to the river Dora Riparia down-
stream of the Gorge dam: in part
through a regulation valve situated on
the body of the dam, which ensures a
minimum vital flow and in part throu-
gh a demodulator tunnel with a circu-
lar cross section, which branches off
from the pressure return tunnel and
conveys the water to a point about
700 m downstream of the dam.
The Plant of
Pont Ventoux-Susa
Pont Ventoux-Susa plant
Salbertrand-Chiomonte and Chiomonte-Susa plants
In Clarea Valley, on the right side of the
valley outside the bed of the Clarea tri-
butary, a daily regulation reservoir has
been built with a net regulation volume
of 571,233 m3, which corresponds to a
maximum regulation level of 1,030.50
m a.s.l. The total length of the crest of
the reservoir is 852 m.
The reservoir was constructed by cre-
ating an artificial bed in the Clarea tri-
butary running alongside the reservoir.
The design solution adopted maintains
the surface flow of the Clarea tributa-
ry continuous without its water mixing
with the water in the river Dora Riparia
contained in the reservoir.
This was done to safeguard the flu-
vial ecosystem of the Clarea tributary
downstream of the regulation reservoir.
All the hydraulic works necessary for the
supply of the reservoir, diversion and di-
scharge of the water were built under-
ground, on the rocky right side of the
valley. The discharge works were tested
by hydraulic physical modelling.
A pressure tunnel with a circular cross
section dug with a TBM, 4.3 km long and
with a final diameter of 4.05 m, sized for
a maximum flow rate through the tur-
bine of 34 m3/s, links the regulation re-
servoir of Clarea Valley to the upstream
piezometric well. The latter consists of a
cylindrical shaft with a height of about
80 m carved into the solid rock.
The piezometric well is the starting
point of the forced pipeline, which is
also entirely carved into the rock and
consists of a metal pipeline 1,320 m
long with a variable diameter (3.50 –
3.20 – 2.80 m).
The Pont Ventoux-Susa run-of-river plant
is regulated on a daily basis and takes
water mainly from the river Dora Ripa-
ria between Pont Ventoux (municipality
of Oulx) and Susa but also from the left
tributary, Rio Clarea.
The main diversion works on the river
Dora, situated at Pont Ventoux, con-
sist of a barrier dam including a fish
ladder, intake works and a moderator
canal on the left bank that houses the
gravel and sand removers.
The altitude to which the reservoir is
normally regulated upstream of the
barrier is 1,046.30 m a.s.l.
The design of the hydraulic works
in the river bed, including the dikes
upstream and downstream of the bar-
rier was tested by physical modelling.
A minimum instantaneous release
(minimum vital flow) from the bar-
rier is guaranteed to preserve aquatic
life in the river before other tributari-
es flow into it.
The water from the river Dora Riparia
(mean diverted flow rate 9.51 m3/s)
is conveyed into an off-take canal in
a free-surface tunnel, sized for a ma-
ximum flow rate of 33 m3/s.
The canal runs on the left side of the
river Dora Riparia for about 14 km to
the Clarea Valley reservoir.
The electric power plant was built in an
underground cavern with an excavation
volume of about 35.000 m3.
The machine room level is situated at
495.00 m a.s.l. and is accessible from
the mouth of the cavern situated at a
height of 575.00 m a.s.l., on the Susa-
Venaus road, through a large tunnel su-
itable for the transit of lorries and about
1,170 m long.
The plant is also equipped with an esca-
pe tunnel about 460 m long. The tran-
sformers are installed in underground ca-
verns independent of the machine room.
The plant in the cavern houses the
hydraulic and electrical production ma-
chinery: a two-component unit (Fran-
cis turbine and generator) and a th-
ree-component unit (Francis turbine,
generator and pump), both with a ver-
tical axis and an overall efficient power
of 150 MW.
The pump, which has a maximum ca-
pacity of about 13 m3/s, transfers wa-
ter from the Gorge reservoir of the ri-
ver Dora Riparia to the regulation Clarea
Valley reservoir.
In this way, the water is made available
again in the Clarea Valley reservoir, thus
ensuring a significant additional pro-
duction of electricity for use during the
daytime when the demand is higher,
thus optimizing the use of the amount
of water available.
The high-voltage connection with the
national transmission grid is made at
the Terna transformer station in Ve-
naus by means of underground cables
to the armoured electric power plant
situated at the mouth of the tunnel for
access to the plant in the cavern.
Downstream of the plant is situated
the tunnel pressure return canal, which
is about 1.6 km long and leads into the
bed of the river Dora Riparia upstream
of the town of Susa. In order to ensu-
re the necessary demodulation of the
flows and pump storage, a concrete
arch-gravity dam was built to form a
reservoir at the gorge of the river Dora.
The body of the dam, which has a vo-
lume of about 48.000 m3, reaches a
maximum height above the river bed
of about 30 m, and has a crest about
90 m long. The net storage volume
at its maximum regulation height of
531.20 m a.s.l. is 442,200 m3.
The entire barrier permits overflowing
via four overflow thresholds that con-
verge towards a damping reservoir
downstream of the dam.
A concrete cofferdam was built im-
mediately upstream of the dam to al-
low dam construction and subsequent
maintenance work to be carried out.
The water diverted and used is retur-
ned to the river Dora Riparia down-
stream of the Gorge dam: in part
through a regulation valve situated on
the body of the dam, which ensures a
minimum vital flow and in part throu-
gh a demodulator tunnel with a circu-
lar cross section, which branches off
from the pressure return tunnel and
conveys the water to a point about
700 m downstream of the dam.
The Plant of
Pont Ventoux-Susa
T H E H Y D R O E L E C T R I C P O W E R P L A N T O F P O N T V E N T O U X - S U S A
w w w . i r e n e n e r g i a . i t
Iren Energia is the company in the Iren Group whose core
businesses are the production and distribution of electri-
city, the production and distribution of thermal energy for
district heating and the provision of technological services
Iren Energia constantly pursues its objectives, which are qua-
lity, reliability, sustainable development, energy efficiency
and a close relationship with the areas in which it operates.
The hydroelectric power plant of Pont Ventoux-Susa
has an installed capacity of 150 MW and uses water
from the river Dora Riparia and its tributary Rio Clarea.
The water is conveyed along an off-take canal in a tun-
nel to the Clarea Valley reservoir, the starting point of the
pressure tunnel leading to the forced pipeline, which, in
turn, leads to the plant in the cavern.
Downstream of the plant the water is returned to the Gor-
ge della Dora reservoir and may be pumped back at night-
time to the Clarea Valley reservoir, so that it can be reused
to produce electricity during the daytime.
MAIN PLANT CHARACTERISTICS
Pont Ventoux intake works Altitude considered normal 1,046.30 m a.s.l.
Clarea Valley reservoir Altitude considered normal 1,030.50 m a.s.l.
Capacity 561,000 m3
Gorge reservoir Altitude considered normal 531.20 m a.s.l.
Capacity 442,000 m3
General information Subtended catchment basins 536 km2
Maximum net head 502.92 m
Efficient power 150 MW
Mean energy coefficient 1.23 kWh/m3
Mean power output per year of over 350 GWh
Iren Energia S.p.A.Corso Svizzera, 9510143 Torino - ItalyTel. +39 011 5549 111Fax +39 011 53 83 13
Cutaway of plant in cavern (three-component unit)
The Hydroelectric Power Plant of Pont Ventoux-Susa oc
tobe
r 20
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