Water Power and Dam Construction. Issue November 2010
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WWW.WATERPOWERMAGAZINE.COM NOVEMBER 2010 21
PUMPED STORAGE
short life (in comparison with the life of a power plant), and the
space required makes them an unattractive option. Space and main-
tenance costs are other associated issues. Batteries also often suffer
from memory effect (something observed in rechargeable batteries
that causes them to gradually lose capacity over time).
rPumped storage on the other hand is a well developed and matured
technology and provides a solution for energy storage amounting to
up to 2000MW. Pumped storage can store thousands of megawatts
over a daily and seasonal period, and has the ability to quickly
adapt to real time requirements. Currently pumped storage has
an edge over other energy storage technologies and may provide a
solution to the intermittent nature of renewables.
SPANISH POWER
A case in point is Spanish power utility Iberdrola. Among other sev-
eral existing generation technologies available to stabilise the vari-
ability of wind capacity, Iberdrola chose pumped storage, which is
always available and provides signicant exibility with regard to
start ups and shutdowns. Iberdrola Renovables is a subsidiary of the
Iberdrola Group and has a total installed capacity of 11,010MW.
Out of this, 5587.60MW has been installed in Spain since June
2010. Among all the renewable sources; wind contributes the most.
The company optimises its wind resources with the integration of
pumped hydro.
Iberdrola has the 635MW La Muela pumped storage facility and
is building the 852MW La Muela 2 pumped storage plant in order to
integrate wind and its other renewable sources. The company is fur-
ther investigating the construction of three additional pumped storage
plants with a total capacity of 1640MW.
GLOBAL TRENDS
According to GlobalData research; the current global pumped stor-
age installed capacity is approximately 132GW. Japan, the US and
China are the world leaders in pumped storage installation. Many
countries around the globe have plans to aggressively increase their
pumped storage capacity.
In response to environmental concerns, renewable energy resourc-
es are being promoted all over the world with the help of various
policy measures and incentives. However the issue of intermittence
is an obstacle and is hindering the rapid growth of these clean sourc-
es of energy. Pumped storage may play an important role in the fast
development of renewable energy technologies – which are sporadic
by their very nature. Countries, along with leading wind power
producers, are focusing on the fast development of pumped storage
facilities. Its grid friendly characteristics – such as frequency-voltage
balancing, reserve generation, optimisation of base loads clubbed
with renewable energy integration; make it one of the best energy
storage technologies. The technology will certainly attract large
investments in years to come and is expected to be a major hot-spot
for investment by various energy utilities in the world.
Purushottam Uniyal is an Analyst with the Alternative
Energy Team at GlobalData
Above: Iberdrola is currently building the 852MW La Muela 2 pumped storage
facility to integrate wind and other reenewable resources
Right: Further view of the existing 635MW La Muela project. Photographs
courtesy of Iberdrola
IWP& DC
22 NOVEMBER 2010 INTERNATIONAL WATER POWER & DAM CONSTRUCTION
NEW HYDRO DEVELOPMENT
T
HE long term political context for hydropower in Europe
is at the same time challenging and interesting. The over-
all goal of the Renewables Directive (2009) is that 20%
of total European energy consumption shall come from
renewable sources by 2020. At the same time the Water Framework
Directive of 2000 (WFD) aims to improve the aquatic quality of
all water bodies, including riverbeds downstream of hydropower
dams, by 2015.
In order to preserve aquatic ora and fauna, many hydropower
dams are obliged to release a certain amount of water for all or parts
of the year. This release is called the reserved environmental ow,
and the implementation of the WFD will give a substantial increase
in such ows. As one example EDF, the largest French hydropower
producer, has estimated the consequences of implementing the WFD
is equivalent to shutting down an 800MW power plant.
CleanPower AS based in Kristiansund, Norway has developed a
combined axial turbine and generator called the Turbinator. This is
particularly well-suited for producing hydropower from environmen-
tal outlets. Besides being optimised for the right ow/head window, it
is compact, has a fully sealed generator cooled by the water ow, and
accommodates a simple installation site not even needing a power
house. A pilot installation was completed in 2010 in cooperation with
European renewable energy producer Statkraft AS.
TECHNICAL DESCRIPTION
The Turbinator is a low head axial turbine where the turbine and
generator are integrated, making a compact unit with small footprint.
The turbine has a xed pitch runner and the pilot model has a vari-
able pitch guide vane assumed to become xed in the nal version.
The generator is a permanent magnet synchronous machine, fully
designed by CleanPower. The rotor of the generator with perma-
nent magnets is xed directly to the outside of the turbine runner
(tip driven), meaning the entire generator / turbine assembly has
one single rotating piece. On the upstream side, the Turbinator has
a simple bolted ange connection to the pipe, and a suction pipe
downstream completes the water way.
The control system features fully autonomous operation under
remote surveillance and is adaptable to customer requirements which
could in future include complex algorithms for optimized production.
DEVELOPMENT
The turbine was designed by Evald Holmén of Sweden. He has
designed turbines for half a century, and is an internationally
renowned expert on hydropower turbines. The design is based on a
Kaplan turbine he has previously worked with, by transforming the
waterway in front of the runner to the required tubular shape. Model
tests on that Kaplan turbine showed a peak efciency of 92.2 %. The
model turbine was a normal Kaplan design with a spiral casing and
guide vanes. Its eight-blade design gave a margin in cavitation resist-
ance. A relatively big hub diameter on the model turbine eliminated a
part of the difference in runner inlet velocity as function of the radius
between Kaplan and tubular turbines.
The model test data estimated that for the required performance,
a runner diameter of 660mm and a blade angle of 19 degrees was
required. In the simple tubular design it was contemplated to have
guide vanes in a xed position, but the transformation of the guide
vanes from an axial ring to a radial ring made it difcult to estimate
the optimum cam angle for the guide vanes. In this pilot model a
movable guide vane ring having 18 vanes was therefore installed.
From measurements of the pilot model at different heads a calibra-
tion of the on cam angle can be made for use in future applications
of the Turbinator – with the intention of having xed guide vanes to
simplify and increase the robust nature of the construction.
Test runs after installation show expected performance data regard-
ing power output. Constraints in the installation makes it difcult to
accurately measure the absolute discharge, but relatively big pressure
losses in the pipe (dia. 450mm) through the dam body makes it pos-
sible to measure relative discharge and to nd the relative efciency.
CleanPower has installed its rst Turbinator at the Hegset dam in Norway. The Turbinator
combines an axial turbine and generator in a compact and sealed machine, and can utilise
lost hydropower potential from environmental outlets
Installing the Turbinator
First water through the generator, with suction pipe opening not yet
submerged. Some residual rotation in the water can be seen.
WWW.WATERPOWERMAGAZINE.COM NOVEMBER 2010 23
NEW HYDRO DEVELOPMENT
It is always the runner that determines the discharge through the tur-
bine in a certain operating point at peak efciency, so the model test
discharge 1.2m
3
/sec was used for calibrating the relative discharge.
The generator is designed by Øystein Krøvel of CleanPower AS.
It is an eight-pole permanent magnetised synchronous generator
with surface mounted magnets. The stator features classic integer
distributed winding with random round wire coils. A special feature
of the generator is the wet air gap, requiring waterproong of both
the magnets and the stator, resulting in a large distance between
rotor and stator. The permanent magnetised rotor is advantageous
compared with induction and eld wound synchronous generators
with a large wet air gap.
The generator is connected directly to the grid without the con-
verter commonly used between permanent magnetised machines
and the grid. Being permanently magnetised, the generator cannot
regulate the voltage and/or the reactive power. The reactive power
ow is thus dependent on the grid parameters, ie the voltage at the
terminals. The design has to take into account the different operating
points choosing a suitable voltage drop to make sure the generator
can operate within the expected range. The chosen grid transformer
has steps, enabling adjustment for larger seasonal changes or more
permanent changes on the grid.
As the generator and turbine designs must match, this implies some
restraints such as turbine speed (maximum rpm and synchronous
speeds) and diameter. The inner diameter of the rotor is the outer
diameter of the runner. This gives a much larger rotor diameter than
what would normally have been chosen for the specied speed and
power rating, resulting in a short machine with a ratio between the
active length and air gap diameter of one-third. The rotor and stator
yokes are kept as thin as possible to minimise the outer diameter of
the machine. The thin yokes are heavily loaded magnetically (to avoid
too high magnetic losses) but still keep the generator slim. It has been
chosen to reduce the magnetic loading by increasing the stator length
somewhat. The successful integration of the generator has given a
slim and compact machine with a very good overall performance,
says CleanPower.
ADVANTAGES
The design of the Turbinator has been focused on achieving a simple
and robust construction where a governing design trade-off has
been to favour simplicity over peak efciency. By this approach the
Turbinator has the potential of opening up for hydropower installa-
tions in sites previously not nancially viable. Its main features are:
r Simple and robust design with only one rotating part.
r Small footprint for cramped installation sites.
r Simple installation to a pipe ange.
r Limited civil works – a simple concrete foundation to
ensure stability.
r Sealed generator efciently cooled by the water stream.
r Can stand outdoors – a protective building is not needed.
r Good efciency.
r Low noise.
EASE OF INSTALLATION
Compared with a traditional small hydropower installation, the
Turbinator demands only very basic preparations and civil works. It
is connected upstream to a pipe ange with a motorised valve that is
governed by the control system. Bolting it to a concrete slab ensures
stability. A downstream suction pipe ensures a continuous water
string all the way to the downstream water level.
The control system is installed in an existing building near the
Turbinator. To enable remote control via internet, this location
needs an internet line (can be wireless via GSM/GPRS or similar).
Signal cables are run between the control system and Turbinator,
and power cables from the Turbinator to the grid transformer via
the control system.
In a traditional small hydropower installation, the non-electrome-
chanical parts are usually around 70% of the total investment. Due to
the simplied installation, non-electromechanical costs are expected
to be less than 50% of the total investment for a Turbinator plant.
Reserved flow from Hegset dam before and after Turbinator installation
View from upstream side, looking into guide vane and runner. Runner wheel assembly
24 NOVEMBER 2010 INTERNATIONAL WATER POWER & DAM CONSTRUCTION
NEW HYDRO DEVELOPMENT
PILOT INSTALLATION AT HEGSET DAM
The rst full scale demonstration model was piloted at the Hegset
dam in August 2010. Located on the Nea river in Sør-Trøndelag
county, Norway, the dam has an environmental outlet obligation of
1.5m
3
/sec during ve summer months, with the measurement point
situated 6km downstream. The environmental outlet pipe through
the dam is slightly under dimensioned, providing an estimated 1.2m
3
/
sec from the dam, but water from adjoining creeks adds up to ensure
the required minimum ow at the measurement point. The Nea river
is known for good trout shing, so all necessary precautions must be
taken to preserve the aquatic environment.
As a known limitation for the project, the 450mm pipe through the
dam gives an estimated 4m pressure loss, around 15% of the gross
head. The gross tidal range is 24.6-30.6m.
As this is a new design with unproven characteristics, the pilot instal-
lation was awarded public co-funding through Innovasjon Norge (the
state-owned company in charge of such funding in Norway). The
total project cost was around €690,000 (US$) including extensive
development and engineering activities, and a non-optimised supply
chain including a custom-built generator.
The Turbinator pilot model installed was completed on 14
October 2010. It had been operational more than 98% of the
time. Most of the down-time was after automatic shut-downs due
to nightly power outages. The pilot plant has during 1500 run-
ning hours in 2010 delivered 0.35GWh (average of 234kW). The
Turbinator has been disassembled and inspected. It will be stored
for the winter before being installed again in April, ready for the
start of the next season on 1 May 2010.
FURTHER DEVELOPMENT
Looking to the future, the primary objective for the Turbinator is
to industrialise the design. All necessary adjustments to minimise
manufacturing costs need to be carried out. This includes dening
physical standard sizes within which the runner and generator will
be adapted to t the data for each installation site. For some sites
adding a frequency converter would increase the system exibility. It
would enable voltage and reactive power regulation, and also enable
runner speed adjustments that would in turn adjust optimum operat-
ing point and water ow as a function of head. The advantages of
adding a frequency regulator must be balanced against added cost
and power losses.
Optimum congurations for non-grid operation (eg autonomous
powering of a rural village) will be studied, as well as advanced
bearing systems, which could be permanent magnet or water cooled
composite based bearing systems.
The authors are Egil Opsahl, Managing Director
CleanPower AS, Kristiansund, Norway, Evald Holmén,
Evald Holmén Consulting, Stockholm, Sweden, and
Øystein Krøvel, Tech Manager, CleanPower AS,
Kristiansund, Norway.
www.cleanpower.no
45
40
35
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25
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Reactive power (kVAr)
Voltage (V)
050 100 150 200 250
Delivered power (kW)
Reactive
power
Voltage
110
100
90
80
70
60
50
40
2.00
1.75
1.50
1.25
1.00
0.75
0.50
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/sec)
0.55 0.60 0.65
Relative efficiency
n11 (rpm)
n11_25.5 n11_27 n11_30
rel_eff_25.5 rel_eff_27 rel_eff_30
45
40
35
30
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10
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0
423.5
423.0
422.5
422.0
421.5
421.0
420.5
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5
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5
0
5
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5
0
5
0
4
4
4
4
4
4
4
4
4
4
Reactive power (kVAr)
Voltage (V)
050 100 150 200 250
Delivered power (kW)
Reactive
power
Voltage
110
100
90
80
70
60
50
40
2.00
1.75
1.50
1.25
1.00
0.75
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Q11 (m
3
/sec)
0.55 0.60 0.65
Relative efficiency
n11 (rpm)
n11_25.5 n11_27 n11_30
rel_eff_25.5 rel_eff_27 rel_eff_30
Who’s who?
The companies involved in the Turbinator pilot project were:
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IWP& DC
Pernegg canal, Austria 2010 – Rehabilitation of the canal walls by PVC
geocomposite, exposed on the lower part and covered by boulders on the
upper part. Hydropower.
CARPI SYNTHETIC GEOMEMBRANES
HAVE STOPPED LEAKAGE IN 100 + DAMS
Since 1963
GEOMEMBRANES ARE:
1,200 + projects completed. Design and supply of waterproofing systems for
dams, canals, hydraulic tunnels, reservoirs. Dry and underwater installation.
t*NQFSNFBCMF
t'MFYJCMF
t3FTJTUBOUUPTFUUMFNFOUT
t*OTUBMMFERVJDLMZ
also underwater
t%VSBCMF
t"QQMJDBCMFUPBMMUZQFT
of structures
t&OWJSPONFOUBMMZGSJFOEMZ
t&GGJDJFOUMZNPOJUPSFE
CARPI TECH
Via Passeggiata 1 6828 Balerna - Switzerland
Ph. +41-91-69540000 Fax. +41-91-6954009
www.carpitech.com e-mail: info@carpitech.com
Carpi_nov10.indd 1 10/11/10 10:25:51
26 NOVEMBER 2010 INTERNATIONAL WATER POWER & DAM CONSTRUCTION
REHABILITATION
I
N the eld of hydropower, sometimes what is old becomes new
again. Such is the case with the historical hydroelectric plant at
Stuyvesant Falls, New York in the US. It was built at the turn
of the 20th century to supply power to a 60km long electric
railroad that opened for business in November 1900. The third-rail
line was considered the longest road of its type and stretched between
Hudson and Albany, New York, deriving its 600V direct current
power from the dam and power station on Kinderhook Creek.
The hydroelectric power facility, owned by the Albany and
Hudson Railway and Power Company, included a dam, water con-
veyances, powerhouse and generating equipment. The dam, abutted
by the creek’s natural rock walls, was constructed of coursed ashlar
limestone with Portland cement mortar and stood 4.1m high and
79.3m wide. At the east end of the dam, a water intake of cut stone
with concrete overlays guided water into two riveted steel penstocks.
The intake, which was 3m wide and 13m high, included two steel
head gates and a steel taintor gate and trash sluice. The penstocks
measured 2.2m in diameter, with thicknesses ranging from 3/16 to a
½-inch, and extended 871m downstream of the dam to the power-
house. Built with local brick, the powerhouse had gable-end construc-
tion, measured 24.9m x 43.2m in plan and stood 10.6m high. On
the south side of the powerhouse, the downstream bay stood three
stories high and ran the full length of the building. The lowest level of
the south bay enclosed the turbine cases, the second level housed the
low-voltage switchboards and transformers, and the third level held
the high-voltage switchboards.
Historic beacon
of green power
James A Besha, president of Albany Engineering Corporation in the US, gives an historical
insight into the rehabilitation of the Stuyvesant Falls hydro project in New York State
WWW.WATERPOWERMAGAZINE.COM NOVEMBER 2010 27
REHABILITATION
The power station housed ten Francis-type turbines in horizon-
tal pressure cases. The turbines ranged from 0.38m diameter, single
runner turbines to 0.84m double runner turbines. Three 0.84m diam-
eter turbines operating at 375rpm drove 750kW, 12,000V, three-
phase 25Hz generators. Power from these units was transmitted to
remote substations where it was converted to direct current for trac-
tion power for the railway.
Three 0.53m turbines, operating at 600rpm, drove both 125kW
and 50kW generators operating at 2200V, single-phase, 60-cycle for
lighting circuits and transmission to communities along the railway
system. Local traction supply for the rail line was furnished by two
0.76m turbines operating at 450 rpm, which drove generators of 200
kW capacity, each operating at 600 V direct current. Excitation for all
generators was produced by two 0.38m turbines operating at 975rpm
that powered two 45kW, 60V direct current generators.
Lombard hydraulic governors controlled all the turbines. The 25Hz
alternating current generation was stepped up at the powerhouse to
either 11,000V or 22,000V for transmission to three remote substa-
tions. At the remote substations the alternating current was stepped
down to 380V, then commutated to 600V direct current by rotary
converters that powered the third rail of the railway.
Understanding its obligation to provide reliable service even during
times of low water or other disruption, the railroad company inte-
grated a steam plant with the hydro plant to generate supplemental
electric power. The steam plant comprised two triple drum water boil-
ers of 1750HP each. Steam was generated in 150 psig and supplied
to marine-type condensing engines, the largest of which had 1.22m
diameter cylinders. The engines were belted to each of the 750kW
alternating current generators and to the 250kW lighting generators.
The steam plant ran on heavy fuel oil transported to the plant through
a 0.15m diameter pipe supply line running over the Kinderhook Creek
from an oil storage depot adjacent to the rail line.
The combined hydro and steam plant’s highest production was
in 1937 when it generated 15,952MWh. The railroad shut down
in 1929, and over the years the plant underwent changes in owner-
ship, use and conguration. This included substantial changes to the
hydroelectric generating equipment and abandonment of the steam
generation system.
GENERATION
In 1942, under the demands of a rapidly accelerated war effort and
the need for more power, a turbine-generator set from the Spiers
Falls hydroelectric plant (located nearby on the Hudson River) was
relocated to the Stuyvesant Falls facility to replace the original gen-
erating equipment. The turbine, manufactured by Allis-Chalmers
Manufacturing Company in 1917, was a 1.10m diameter double
runner Francis turbine housed in a horizontal, double spiral case. At
Spiers Falls it had operated at 22.86m of head, but at Stuyvesant Falls
it would operate at closer to 30.48m. The generator, built in 1904,
was a General Electric Model ATB, which produced 3500kVA, at
2400V, three-phase, 0.8 power factor. It was originally a 40Hz unit
operating at 240rpm but was rebuilt in 1942 to withstand the higher
speed of 360rpm, which allowed for 60Hz operation. However, its
3500kVA capacity was signicantly less than the output of the tur-
bine now operating at a much higher head.
Though all the hydraulic turbines and generation equipment were
replaced, the 1942 plant modications retained the civil features
including the dam, intake and penstocks. In order to generate more
power, a substantial increase in hydraulic capacity for the penstocks
resulted in increasing the velocity of the conveyed water. This had the
effect of inducing considerable head loss; while the design was not
optimal, it was done under war-effort pressure to increase generation
requirements. The year 1945 was one of the best generation years on
record when the plant produced 19,544.4MWh. The lowest genera-
tion on record was 49MWh in 1979.
NEW CENTURY, RENEWED PLANT
Age, deterioration and changing times forced the plant into obsoles-
cence toward the end of the 20th century. The owner at that time,
Niagara Mohawk Power Company, terminated operation and sur-
rendered the licence in 1996. In 2002 the Town of Stuyvesant (where
the plant is located) contacted Albany Engineering Corporation for
assistance in developing the plant.
Albany Engineering, based in Albany, New York, specialises in
hydroelectric design and development and has a diverse portfolio
of projects ranging from 1.5MW under-river powerhouses to a
260MW pumped storage scheme using an abandoned mine. But
the rm also has a demonstrated interest in historic plants, having
restored its own 1897 plant in Mechanicville and the 1921 Henry
Ford plant at Green Island, both located in New York on the
Far left: Early view of the project, built at the turn of the 20th century;
Left: GPS-enabled sonar allows the Albany Engineering Corporation crew to
map underwater contours of the dam and reservoir
Far Left: Powerhouse interior, 1943. Middle and left: Unloading the new stator
28 NOVEMBER 2010 INTERNATIONAL WATER POWER & DAM CONSTRUCTION
REHABILITATION
Hudson River. The Mechanicville plant, still running on its original
40-cycle equipment, is considered the oldest continuously operating
hydro plant in the US.
Founded in 1924, Albany Engineering Corporation prides itself on
its innovative approach to hydropower projects while working within
the environmental context and historic integrity of each project. As
an example, the renewed plant at Stuyvesant Falls will incorporate
extensive environmental protection measures to safeguard resident
and migratory sh species. Albany Engineering will install an intake
system of its own design that offers extensive protection for sh, pre-
venting their entrainment and impingement.
This fish passage and protection system comprises a state-of-
the-art, positive exclusion inclined screen system constructed of a
water-ballasted-steel space frame that supports injection-moulded
polycarbonate screen panels. The system uses a high ratio of sweep-
ing velocity to through velocity that facilitates the passing of sh and
debris to the apex of the screen system where it is then passed down-
stream via a pipe conveyance.
The 1942 Spiers Falls turbine will not be used in the new plant due
to a penstock conguration that results in signicant head loss and
limited turbine output. Its accompanying generator is also undersized
for the turbine. They will be replaced by two identical vertical Francis
turbines, manufactured by Allis-Chalmers, with runner diameters of
1.12m with concrete spiral cases and elbow draft tubes. The turbines
will be directly connected to vertical generators manufactured by
Westinghouse Electric Company. These two turbines and generators,
originally installed at the Osage hydro plant at Lake of the Ozarks,
Missouri, are a perfect t.
The vertically congured units will permit installation of the gen-
erators above ood level, correcting a deciency existing in both the
original 1899 and 1942 congurations. The new units have a gener-
ating capacity of approximately 3000kW each, operating at 4160V,
60Hz alternating current at 1.0 power factor. The units, which oper-
ated until they were removed from Osage in 2009, are undergoing
complete refurbishment.
REFURBISHMENT
The new facility will use the existing 1899 dam and intake (rehabili-
tated in 1979). Leaks, erosion, corrosion and other factors of time
have affected the original penstocks. The two original steel penstocks
will be cleaned using high pressure water-jet blasting; some sections
will be replaced, and the interior throughout will be relined with a
modern polyurea coating system. After refurbishment, the penstocks
will make their transition to the turbines with their new hydrauli-
cally optimised terminal portions positioned safely beneath oor level
and encased in concrete. The deteriorated, original 1900 surge relief
towers will be replaced by synchronised bypass valves, hydraulically
connected to the turbine wicket gates, to assist in minimising pressure
surges during turbine operation.
Rehabilitation plans include installation of new unit breakers and
switchgear, station service, transformer, fused disconnect switches, and
lighting and surge arrestors. New turbine and generator controls and
protective devices will be installed in accordance with the requirements
of the local transmission provider, National Grid. New solid-state excit-
ers, lubrication and cooling systems, and hydraulic pressure units will
also be installed. New drive motors, hoist chain/cables, remote controls
and safety devices will update the powerhouse crane. A programmable
logic controller will operate the new equipment automatically with dig-
ital protective relaying and digital synchronisers.
The new plant equipment will use approximately 21.24m
3
/sec,
operating with a gross head of 30.48m and a net head of approxi-
mately 29.8m. The new generation facilities will be connected to the
National Grid transmission system through an adjacent 34,500V
switchyard. The newly expanded facility will generate approximately
20,000MWh annually.
The project is currently being relicensed under the Federal Energy
Regulatory Commission regulations. Plans to install minimum ow
turbines and generators at both the intake and powerhouse are
included in the relicensing. The combined capacity of these units
will be 900kW.
Because the plant is in the Stuyvesant Falls Historic District, the
powerhouse exterior will be restored carefully, including refurbish-
ment of windows and doors. The exquisitely detailed brickwork will
be re-pointed and repaired. Other updates include a potable water
supply, sanitary waste disposal facilities, lighting, security systems
and communications systems.
GREEN ENERGY
Construction work began in January 2010 and should be completed
by June 2011. Testing and commissioning will take place through the
fall of 2011. The planned rehabilitation of the hydroelectric station,
generating approximately 7.9MW, is scheduled for completion in
late 2011. And thus, Albany Engineering Corporation will bring this
century-old plant to life once again, supplying electricity to the region
as an historic beacon of renewable green energy.
The author is James A Besha, president,
Albany Engineering Corporation, 5 Washington Square,
Albany NY 12205, US.
Contact: Info@albanyengineering.com
IWP& DC
Above: Staff work together to remove an existing turbine in preparation for
the installation of the new turbines
ADVANCING
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OPERATION AND MAINTENANCE
Sayano Shushenskaya accident
– presenting a possible direct cause
The cause of a fatal accident that occurred on 17 August 2009 at the Sayano Shushenskaya
Dam and powerhouse in Southern Siberia has never fully been revealed. In this peer-reviewed
paper, F A Hamill presents a hypothesis of the underlying direct cause of the accident
30 NOVEMBER 2010 INTERNATIONAL WATER POWER & DAM CONSTRUCTION
I
T has now been over a year since the catastrophic accident
at the huge Sayano Shushenskaya Dam and Hydroelectric
Station in southern Siberia which cost the lives of 75 people
and nearly destroyed the 6400MW powerhouse.
Initially, the accident was lightly reported in the west, both in the
mainstream and the technical press. Over the ensuing months, the
early internet postings of photographs, videos and narratives from
witnesses and technical experts in Russia [references 1 through 8]
were supplemented with studies, opinions and speculations about
causes from writers both inside and outside of Russia.
So far, this writer has not seen a complete and credible explanation
of how this accident, with its very violent sequence of events, could
have been caused. Both the ofcial reports issued after the incident,
and several technical discussions that followed, have drawn very gen-
eral conclusions that attributed the incident to heavy vibration and
poor maintenance associated with failed studs in the turbine head
cover of Unit 2 in the plant. This article has been prepared to offer
a hypothesis as to the underlying direct cause of the accident. This
is done in the interest of promoting safety awareness among owners,
engineers, managers and operators of hydro plants everywhere.
This hypothesis is that the explosion was caused by water
column separation in the draft tubes of the destroyed units. This
condition can readily be caused by a too-rapid wicket gate clo-
sure during unit load rejection. Adjustment of governor times to
unsafe values to achieve fast response to operating load changes
may have occurred in recent times in response to a need to improve
grid frequency control. This, combined with compromised stud
connections due to poor maintenance, can explain the extreme
violence of this accident.
Complete and detailed technical data, such as drawings and data
sheets, have not been available to support a full-scale technical paper
on this subject. Therefore, the conclusions presented in this article
are speculative. The importance of the safety issue to the profession
and the industry, however, is such as to dictate that this analysis be
presented, however incomplete.
THE ACCIDENT
At 08:13 and 25 seconds local time on 17 August 2009, Unit 2
experienced a load rejection, which was followed immediately
by a loud bang heard in the administration and control build-
ing adjacent to the powerhouse. The load rejection precipitated
a massive failure involving the lifting of runner, shaft, head
cover, turbine and generator bearings vertically upward into the
umbrella generator rotor spider, destroying it. Full penstock
head was then released into the turbine pit, resulting in an enor-
mous geyser and massive destruction. [9, 10]
At least a half minute
after the geyser blew the
roof away, another very
loud bang was recorded
by a cell-phone video
which showed events as
seen from a substantial
distance downstream from
the powerhouse. [11]
Three units (2, 7 and
9) were totally destroyed.
The rest of the units were
severely damaged, with
the exception of Unit 6,
which was under refur-
bishment and not in
operation. [10] Seventy-
five people died in the
ooded powerhouse. [9]
Above, from left to right: Figure 1 – Sayano Shushenskaya Dam and
Powerhouse (1, 8); Figure 2 – Powerhouse from downstream (8)
Below: Figure 3 – Sectional elevation through the dam and powerhouse (2)