Uploaded by Vadim Eisner

Wave-Energy

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WAVE ENERGY
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INTRODUCTION
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Introduction
• Waves are created by the gravitational action
of sun and the moon and also by the
interaction of wind with the surface of the
sea.
• Wave power is practically inexhaustible and
classified as a renewable energy source.
• Wave energy can be extracted and converted
into electricity by wave power machines. They
can be deployed either on the shoreline or in
deeper waters offshore.
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Introduction
• Wave energy fluxes in open sea or against
coasts may vary from a few watts to kilowatts
per metre. In favourable locations, wave
energy density can average 65 megawatts per
mile of coastline.
• The total power of waves breaking on the
world's coastlines is estimated at 2 to 3 million
megawatts.
• They are smallest in summer and greatest in
winter.(Westerlies and the Trade winds.)
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Introduction
• Wave motion consists of both vertical and
horizontal movement of water.
• Individual particles of water undergo almost a
circular motion, moving up as the crest
approaches, forward at the crest, down as it
recedes, and backward in the trough.
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APPROACHES TO CAPTURE
WAVE ENERGY
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1.Float or Pitching Device or
buoyant moored device
• The device floats on or just below the surface of the
water and is moored to the sea floor.
• A wave power machine needs to resist the motion of
the waves in order to generate power: part of the
machine needs to move while another part remains
still.
• In this type of device, the mooring is static and is
arranged in such a way that the waves motion will
move only one part of the machine. Electricity is
generated from the bobbing or pitching action of a
floating object which can be mounted to a floating
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raft or to a device fixed on the ocean floor.
2.Oscillating Water Columns
(OWC)
• An oscillating water column is a partially
submerged, hollow structure that is installed
in the ocean.
• It is open to the sea below the water line,
enclosing a column of air on top of a column
of water.
• Waves cause the water column to rise and fall,
which in turn compresses and depresses the
air column.
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Oscillating Water Columns (OWC)..
• This trapped air is allowed to flow to and from
the atmosphere via a Wells turbine, which has
the ability to rotate in the same direction
regardless of the direction of the airflow. The
rotation of the turbine is used to generate
electricity.
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3.Hinged contour device
• Here, the resistance to the waves is created by
the alternate motion of the waves, which
raises and lowers different sections of the
machine relative to each other, pushing
hydraulic fluid through hydraulic pumps to
generate electricity.
• A hinged contour device is able to operate at
greater depths than the buoyant moored
device.
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Hinged contour device…
• These shoreline devices, also called "tapered
channel" systems, rely on a shore-mounted
structure to channel and concentrate the
waves, driving them into an elevated reservoir.
Water flow out of this reservoir is used to
generate
electricity,
using
standard
hydropower technologies.
• The main problem with wave power is that
the sea is a very harsh, unforgiving
environment.
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Hinged contour device
• An economically-viable wave power machine
will need to generate power over a wide range
of wave sizes, as well as being able to
withstand the largest and most severe storms
and other potential problems such as algae,
barnacles and corrosion.
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ADVANTAGES
&
DISADVANTAGES
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Advantages
• A much greater extent of power is concentrated
in the motion of waves than in the movement
of air. Whereas the power density at a good
wind energy site may be of the order of a few
square metre, the power density in a
corresponding area of wave motion may be up
to 100 times greater.
• It produces no greenhouse gases or other
waste.
• It needs no fuel.
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Advantages…..
• Wave energy has this advantage over wind or
solar energy that the energy has been
naturally concentrated by accumulation overtime and space and transported from the
point at which it was originally present in the
winds.
• Wave power devices do not use up large land
masses like solar or wind.
• It produces electricity reliably.
• It is free and renewable energy source.
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Advantages…..
• These devices are relatively pollution free, and
because they remove energy from the waves,
the water is left in a relatively placid(calm)
state in their wakes.
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Disadvantages
• The major disadvantage of wave energy, as
compared to wind, is that the energy is
available in the ocean. Therefore the
extraction equipment must operate in a
marine environment which will have to be
taken into account during its construction and
its maintenance ,lifetime and reliability should
be considered since the energy may have to
be transported through a great distance to the
shore.
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Disadvantages…
• There is relative scarcity of accessible sites of
large wave activity.
• Wave energy conversion devices that have
been proposed are relatively complicated .
• Economic factors such as the capital
investment, costs of maintenance, repair and
replacement as well as problems of biological
growth of marine organisms which seem to be
very large, are all relatively unknown.
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Disadvantages…
• Wave energy converters must be capable of
withstanding very severe peak stresses in
storm.
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Challenges to Deploy Wave
Power Devices
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Challenges to Deploy Wave Power
Devices
• Efficiently converting wave motion into
electricity; generally speaking, wave power is
available in low-speed, high forces, and the
motion of forces is not in a single direction.
Most readily-available electric generators
operate at higher speeds, and most readilyavailable turbines require a constant, steady
flow.
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Challenges to Deploy Wave Power
Devices…
• Constructing devices that can survive storm
damage and saltwater corrosion; likely sources
of failure include seized bearings, broken
welds, and snapped mooring lines.
• Knowing this, designers may create
prototypes that are so overbuilt that materials
costs prohibit affordable production.
• High total cost of electricity; wave power will
only be competitive when the total cost of
generation is reduced.
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Challenges to Deploy Wave Power
Devices…
• The total cost includes the primary converter,
the power takeoff system, the mooring
system, installation & maintenance cost, and
electricity delivery costs.
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WAVE POWER POTENTIAL
ALONG THE INDIAN
COASTLINE
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Wave power potential along the Indian
coastline
Location
(Non-monsoon)
Mean wave
height(m)
Mean wave
period(sec)
Wave power
(kW/h)
10-15 N and coast 85 E
(off Madras)
1.14
5.50
7.00
15-20 N and coast 85 E
(off Vishakhapatnam)
1.24
7.10
10.70
20-25 N and 85-95 E
(off Calcutta)
1.72
6.51
18.87
10-15 N and 70 E coast
(off Cochin)
1.01
5.38
5.37
15-25 N and 70 E coast
(off Mumbai)
1.01
5.25
5.24
5 -10 N and 75-80 E
(off Cape Comorin)
1.29
5.46
8.90
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Wave power potential along the Indian
coastline….
Location
(North-east monsoon)
Mean wave
height(m)
Mean wave
period(sec)
Wave power
(kW/h)
10-15 N and coast 85 E
(off Madras)
1.53
5.86
13.44
15-20 N and coast 85 E
(off Vishakhapatnam)
1.60
6.28
15.75
20-25 N and 85-95 E
(off Calcutta)
1.33
8.01
13.88
10-15 N and 70 E coast
(off Cochin)
1.03
5.05
5.25
15-25 N and 70 E coast
(off Mumbai)
1.00
5.00
4.90
5 -10 N and 75-80 E
(off Cape Comorin)
1.22
5.35
7.80
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Wave power potential along the Indian
coastline….
Location
(South-West
monsoon)m
Mean wave
height(m)
Mean wave
period(sec)
Wave power
(kW/h)
10-15 N and coast 85 E 1.71
(off Madras)
5.8
16.62
15-20 N and coast 85 E 2.04
(off Vishakhapatnam)
8.25
33.65
20-25 N and 85-95 E
(off Calcutta)
1.96
7.66
28.84
10-15 N and 70 E coast 2.03
(off Cochin)
6.77
27.34
15-25 N and 70 E coast 2.63
(off Mumbai)
6.93
46.98
5 -10 N and 75-80 E
(off Cape Comorin)
6.29
19.52
1.78
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THANK YOU
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