tidal turbine presentation

Upload: aniket-gaikwad

Post on 07-Apr-2018

220 views

Category:

Documents


0 download

TRANSCRIPT

  • 8/3/2019 Tidal Turbine Presentation

    1/39

    Click to edit Master subtitle style

    www.themegallery.com

    Case Study

    11

  • 8/3/2019 Tidal Turbine Presentation

    2/39

    www.themegallery.com

    La Rance Tidal Power Plant

  • 8/3/2019 Tidal Turbine Presentation

    3/39

    www.themegallery.com 33

  • 8/3/2019 Tidal Turbine Presentation

    4/39

    www.themegallery.com 44

  • 8/3/2019 Tidal Turbine Presentation

    5/39

    www.themegallery.com

    La Rance (240 MW) has beensuccessful as the first full scale

    tidal power plant (1967) , locatedin northern France on the La RanceRiver.

    The dam itself is 2460 feet (750meters) long, and 43 feet (13meters) high.

    The turbines used in La Rance are

    Bulb Turbines (24*10 MW), weigh470tons, Diameter 17 feet.

    The plant is also equipped with

    pumps that allow water to be55

  • 8/3/2019 Tidal Turbine Presentation

    6/39

    www.themegallery.com

    Barrage was large enough to create aroad with two double lanes, saving

    local citizens an eighteen mile drive.The unique nature of the power

    station has also increased tourism inthe area. La Rance attracts over300,000 visitors every year.

    Despite the high initial cost, thepower station has been working for

    over thirty years, generating enoughelectricity for around 300,000 homes.

    66

  • 8/3/2019 Tidal Turbine Presentation

    7/39 www.themegallery.com

    Severn Barrage

    77

  • 8/3/2019 Tidal Turbine Presentation

    8/39 www.themegallery.com 88

  • 8/3/2019 Tidal Turbine Presentation

    9/39 www.themegallery.com 99

  • 8/3/2019 Tidal Turbine Presentation

    10/39

    www.themegallery.com

    The Severn Barrage is a proposedtidal power station to be built

    across the Bristol Channel (SevernEstuary). The River Severn has atidal range of 14 metres - thesecond highest in the world - making

    it perfect for tidal power generation. 20 billion pound ($US30bn) Severn

    Barrage would involve the

    construction of a 10 mile longbarrage (dam) between LavernockPoint south of Cardiff, Wales, and

    Brean Down in Somerset, England.

    1010

  • 8/3/2019 Tidal Turbine Presentation

    11/39

    www.themegallery.com

    The 216 tubular turbines would belocated in the central portion of the

    barrage, and each would drive a 40megawatt generator, resulting in anestimated 17TWh each year (TidalFiles).

    The proposed scheme has a lifetimeof at least 120 years (Taylor, 2002).Ship locks were also included in the

    scheme because the Severn hasmany important ports that would belocated in the tidal basin if the

    barrage was built. 1111

  • 8/3/2019 Tidal Turbine Presentation

    12/39

    www.themegallery.com 1212

  • 8/3/2019 Tidal Turbine Presentation

    13/39

    www.themegallery.com

    Introduction

    The tide induces periodical currentswhich are particularly strong in someseas, in particular along the EnglishChannel.

    The kinetic energy of the currentscan be harnessed by submarine tidalturbines.

    The physical phenomena involvedmust be investigated beforedesigning the suitable equipment.

    The actual resource on a given site1313

  • 8/3/2019 Tidal Turbine Presentation

    14/39

    www.themegallery.com

    The tidal stream resource As a first approach, the power of the

    water stream through a tidal turbinerotor follows a cubic law similar tothe power law of a wind turbine: W =

    . r. U3 - W : power (W.m-2) - r : water

    density = 1024 kg.m-3 - U :water velocity (m.s-1)

    This equation shows that tidal streamenergy is attractive where the tidecreates strong currents. The suitable

    zones are found where the coast1414

  • 8/3/2019 Tidal Turbine Presentation

    15/39

    www.themegallery.com

    Map of the tidal currents in the EnglishChannel. Maximum velocity during a

    mean spring tide

    1515

  • 8/3/2019 Tidal Turbine Presentation

    16/39

    www.themegallery.com

    Race have strongest current about at the moment ofthe high and the low tide, with velocities exceeding 3

    to 4 m.s-1 on large areas.

    1616

  • 8/3/2019 Tidal Turbine Presentation

    17/39

    www.themegallery.com

    The mean spring tide has a coefficientof 95, while the mean neap tide

    coefficient is 45.

    20

    30

    40

    50

    60

    70

    80

    90

    100

    110

    120

    1 31 61 91 121 151 181 211 241 271 301 331 361

    Day of the year

    Tidalamplitude(coefficient

    17Variation of the tide coefficient during the year 2001 atBrest

  • 8/3/2019 Tidal Turbine Presentation

    18/39

    www.themegallery.com 1818

    Power inflow variation during a mean spring tide and a meanneap tide

    0

    5

    10

    15

    20

    25

    -6 -4 -2 0 2 4 6

    Hours relative to local high tide time

    Power(kW/m)

    Ouessant spring tide

    Ouessant neap tide

  • 8/3/2019 Tidal Turbine Presentation

    19/39

    www.themegallery.com 1919

    0

    2

    4

    6

    8

    10

    12

    14

    16

    0 1000 2000 3000 4000 5000 6000 7000 8000 9000

    Cumulative time per year (hours)

    Power(kW/m)

    Cumulative distribution of the power inflow on a site with amaximum velocity of 3 m.s-1 during mean spring tide

  • 8/3/2019 Tidal Turbine Presentation

    20/39

    www.themegallery.com 2020

    0

    5000

    10000

    15000

    20000

    25000

    0 5 10 15 20

    Nominal power input rating (kW/m)

    Theoreticalenergyreso

    urc

    (kWh/year/m)

    Relationship between the power input rating and theannual theoretical energy resource

  • 8/3/2019 Tidal Turbine Presentation

    21/39

    www.themegallery.com 2121

    0

    500

    1000

    1500

    2000

    2500

    3000

    3500

    4000

    2 4 6 8 10 12

    Nominal input power (kW/m)

    Num

    berofhoursp

    eryear Hours at full load

    Equivalent hours of production

    Relationship between the nominal power rating and thehours of production per year

  • 8/3/2019 Tidal Turbine Presentation

    22/39

    www.themegallery.com

    The Marenergie tidalturbine

    2222

  • 8/3/2019 Tidal Turbine Presentation

    23/39

    www.themegallery.com

    Designing parameter of tidalturbine

    The turbine must work in asubmarine environment wheremaintenance is very difficult, so the

    machinery must be made as simpleas possible

    All marine operations for installation

    and maintenance must take intoaccount the strong currentsprevailing in the areas of interest

    A compromise must be found2323

  • 8/3/2019 Tidal Turbine Presentation

    24/39

    www.themegallery.com

    Solution of design of turbine

    The rotor is maintained fixed in thespace and the water flowsalternatively in both directions during

    flood and ebb flows.The number of moving parts exposed

    to the sea water is kept to a

    minimum. The blades are fixed andwelded onto the hub. The onlymoving part in sea water requiringsome attention is the seal of therotor shaft on the nacelle front face.

    2424

  • 8/3/2019 Tidal Turbine Presentation

    25/39

    www.themegallery.com

    choices

    The rotor turns in both directionsfollowing the current direction

    The blades are symmetrical: Both

    ends are alternatively leading andtrailing edges.

    2525

  • 8/3/2019 Tidal Turbine Presentation

    26/39

    www.themegallery.com

    The peripheral velocity is kept at a relatively lowlevel (7m.s-1 ) in order to avoid cavitationphenomena on the blades.

    The optimum velocity decreases when the numberof blades is increased, and a correct velocity isobtained with 6 blades.

    The preliminary studies indicate the benefit of acircular belt at the rotor periphery. This enhances

    the blade efficiency and eliminates most of thepotential vibrations.

    It should also limit the emission of low frequencynoise at the blade tips.

    The outside diameter of a 200 kW rotor is typically10 meters for a nominal current velocity of 3 m.s-1.

    The actual design of the base depends on the soilnature.

    The rotor may be surrounded by a duct if required.Several turbines can be arran ed in arra s2626

  • 8/3/2019 Tidal Turbine Presentation

    27/39

    www.themegallery.com 2727

  • 8/3/2019 Tidal Turbine Presentation

    28/39

    www.themegallery.com

    the power is cancelled for a rotation speed calledfree wheeling speed, slightly higher than the

    optimum speed.

    2828

    0

    50

    100

    150

    200

    250300

    350

    400

    450

    0 5 10 15 20Rotor rotation speed (rpm)

    Power(kW

    )

    1.5 m/s

    2 m/s

    2.5 m/s

    3 m/s

    3.5 m/s

    ELECTRICAL OUTPUT

    Typical characteristics of a Marenergie tidal turbine

    Typical characteristics of a Marenergie

  • 8/3/2019 Tidal Turbine Presentation

    29/39

    www.themegallery.com

    Typical characteristics of a Marenergietidal turbine

    It is not advisable to use the

    maximum hydraulic power of theturbine when the current isparticularly strong.

    The electrical generator is designedwith a nominal power of 200 kW.When the current is sufficient, thepower output is kept at this level.

    The rotor is then stabilized at arotation speed corresponding to theequivalent hydraulic power. Figure

    10 shows that this operation mode is2929

  • 8/3/2019 Tidal Turbine Presentation

    30/39

    www.themegallery.com

    Wave currentinteraction

    The water is put into movement notonly by the tidal streams, but also bythe wave action. The combination of

    both movements is a complexproblem.

    In particular, it is known that a

    current flowing against the swellincreases the wave height while thewaves are attenuated when bothphenomena are in the samedirection. 3030

    Th di t b t t i t i th

  • 8/3/2019 Tidal Turbine Presentation

    31/39

    www.themegallery.com

    The distance between two successive crests is thewave length L which can be calculated by thefollowing implicit relation:

    where g is the acceleration of gravity (9.81 m.s-2)and d is the water depth in the absence of waves.

    The amplitude of the wave movement decreaseswith the depth z below the surface. The horizontalvelocity Vx induced by the wave action is given bythe formula:

    In the absence of wave, the current velocity is zeroon the seabed and highest at the surface. Thevelocity profile is generally approached by the3131

    )2tanh(2

    2

    L

    dgTL

    =

    ))//(2sin(

    )2

    (

    ))(2

    (LxTt

    L

    dCosh

    L

    zdCosh

    T

    HVx

    =

    7/1

    0 )/( zdVVx =

  • 8/3/2019 Tidal Turbine Presentation

    32/39

    www.themegallery.com

    Influence of the swell (H= 2m - T = 9s)on the velocity profiles Water depth =

    30m

    3232

    -30

    -25

    -20

    -15

    -10

    -5

    0

    5

    0 1 2 3 4 5

    Water velocity (m/s)

    De

    pthbelownorma

    lsurface(m)

    Crest passage

    Trough passage

    B h i f th tid l t bi

  • 8/3/2019 Tidal Turbine Presentation

    33/39

    www.themegallery.com

    Behavior of the tidal turbine:Current = 3 m.s-1 - Swell: H= 2m

    T= 9s

    3333

    0.0

    50.0

    100.0

    150.0

    200.0

    250.0

    0 5 10 15 20

    Time (s)

    Output (kW)

    Rotor velocity (rotations per minute x10)

    T i l t t f i l

  • 8/3/2019 Tidal Turbine Presentation

    34/39

    www.themegallery.com

    Typical power output of a singleturbine with waves aligned with

    the current

    3434

    0

    50

    100

    150

    200

    250

    0 1 2 3 4 5 6

    Tidal current velocity (m/s)

    Electricaloutp

    ut(kW) H = 0

    H = 2m - T = 9s

    H = 4m - T = 10s

    H = 6m - T = 12s

    H = 8m - T = 13s

    A t t f f

  • 8/3/2019 Tidal Turbine Presentation

    35/39

    www.themegallery.com

    Average output of an array ofturbines ideally spaced along the

    wave length

    3535

    0

    50

    100

    150

    200

    250

    0 1 2 3 4 5 6

    Tidal current velocity (m/s)

    Electricaloutp

    ut(kW)

    H = 0

    H = 2m - T = 9s

    H = 4m - T = 10s

    H = 6m - T = 12s

    H = 8m - T = 13s

  • 8/3/2019 Tidal Turbine Presentation

    36/39

    www.themegallery.com

    Conclusions

    Tidal streams offer an abundantenergy resource along the EnglishChannel. Tidal turbines can be

    optimized according to the localconditions prevailing on the differentsites.

    The Marenergie tidal turbine isdesigned as simple as possible.Variable speed generators arerequired, similar to the types used inmodern wind turbines. 3636

  • 8/3/2019 Tidal Turbine Presentation

    37/39

    www.themegallery.com

    Advantage It is very cheap

    to maintainThere is no

    waste orpollution

    Very reliable We can predict

    when tides will

    be in or outThe barrage can

    help to reduce

    the damage of

    Disadvantage It changes the

    coastlinecompletely andthe estuaries areflooded so any

    mud flats orhabitats thatbirds or animals

    live on aredestroyed Initial building

    cost is veryex ensive3737

  • 8/3/2019 Tidal Turbine Presentation

    38/39

    www.themegallery.com 3838

  • 8/3/2019 Tidal Turbine Presentation

    39/39

    th ll 3939