Tidal Energy Conversion

1. Btech IIIrd year
Electrical Engineering
Made By:-
Amit Kumar Sharma
Manish Dhiman
Gulzar Ahmed
Mohd. Jasif Qureshi
Submitted To:-
Mr. B.S. Jha Sir

2.  Overview of Tidal Generation
- Tides
- Types of Tides
- History of Tidal Power
- Generation of Tidal Energy
 Generating Methods of Tidal Energy
- Tidal stream generator
- Tidal barrage
- Dynamic tidal power
- Tidal lagoon
 Tidal Turbines
 Types Of Turbines
 Present Tidal Power Plants in the World
 Environmental Concerns
 Advantages

3. What Is Tide??
 Tides are the rise and fall of sea levels caused by the
combined effects of the gravitational forces exerted by
the Moon and the Sun and the rotation of the Earth.
 Some shorelines experience almost two equal high tides
and two low tides each day, called a semi-diurnal tide.
Some locations experience only one high and one low
tide each day, called a diurnal tide. Some locations
experience two uneven tides a day, or sometimes one
high and one low each day; this is called a mixed tide.

4. Types Of Tides
According to the height of the tide
 - High tide: when the sea water reaches its greatest height
within the tide cycle.
 - Low tide: when the sea water reaches its lowest height
within the tide cycle.
According to the lunar phase
- Spring tides
 During the full moon and new moon phases, the Moon
and the Sun are aligned and their effects combined,
producing the spring tides. On the tide tables we can see
the high tidal coefficient of the tides when both celestial
bodies are aligned.
 There is a proven increase in the activity of fish during spring
tides, above all if these coincide with sunrise or sunset, and
these are the most propitious days for fishing.

5. - Neap tides
 During waxing and waning moons, on the contrary, the
effects are detracted, thereby obtaining tides of less
amplitude (lower tidal coefficient), called neap tides.
 The movement on the seabed tends to be less and this
normally results in days that are less propitious for fishing
than days with spring tides.

6. History Of Tidal Power
 787: simple technique of a waterwheel by the Spanish,
French, and British
 1966: “La Rance” tidal power plant went in operation.
 2001: British Parliament states “the world can no longer
neglect the massive potential of wave and tidal energy”
 2002: Large investments in research and prototypes
spark proposals in Turkey, China, and United States;
among others

7. Generation of Tidal Energy: -
 Tidal power is taken from the Earth's
oceanic tides; tidal forces are periodic
variations in gravitational attraction
exerted by celestial bodies.
 These forces create corresponding
motions or currents in the world's oceans.
Due to the strong attraction to the
oceans, a bulge in the water level is
created, causing a temporary increase in
sea level. When the sea level is raised,
water from the middle of the ocean is
forced to move toward the shorelines,
creating a tide.
 This occurrence takes place in an
unfailing manner, due to the consistent
pattern of the moon’s orbit around the
earth. The magnitude and character of
this motion reflects the changing
positions of the Moon and Sun relative to
the Earth, the effects of Earth's rotation,
and local geography of the sea floor and
coastlines.

8. Generating Methods: -
 Tidal Steam Generator: -
Tidal stream generators (or TSGs) make use of the kinetic energy of moving
water to power turbines, in a similar way to wind turbines that use wind to
power turbines. Some tidal generators can be built into the structures of
existing bridges, involving virtually no aesthetic problems. Land constrictions
such as straits or inlets can create high velocities at specific sites, which can be
captured with the use of turbines. These turbines can be horizontal, vertical,
open, or ducted and are typically placed near the bottom of the water column.
 Tidal Barrage: -
Tidal barrages make use of the potential energy in the difference in height
between high and low tides. When using tidal barrages to generate power, the
potential energy from a tide is seized through strategic placement of specialized
dams. When the sea level rises and the tide begins to come in, the temporary
increase in tidal power is channeled into a large basin behind the dam, holding
a large amount of potential energy. With the receding tide, this energy is then
converted into mechanical energy as the water is released through large
turbines that create electrical power through the use of generators. Barrages are
essentially dams across the full width of a tidal estuary.

9.  Dynamic Tidal Power: -
Dynamic tidal power (or DTP) is an untried but promising technology that
would exploit an interaction between potential and kinetic energies in tidal
flows. It proposes that very long dams (for example: 30–50 km length) be built
from coasts straight out into the sea or ocean, without enclosing an area. Tidal
phase differences are introduced across the dam, leading to a significant water-
level differential in shallow coastal seas – featuring strong coast-parallel
oscillating tidal currents such as found in the UK, China, and Korea.
 Tidal Lagoon: -
A newer tidal energy design option is to construct circular retaining walls
embedded with turbines that can capture the potential energy of tides. The
created reservoirs are similar to those of tidal barrages, except that the location
is artificial and does not contain a preexisting ecosystem.

10. Tidal Turbines: -
• Proposed shortly after the oil crisis of
the 1970s, tidal turbines have only
become reality in the last decade, when a
10-15kW 'proof of concept' turbine was
operated on Loch Linnhe. Resembling a
wind turbine, tidal turbines offer
significant advantages over barrage and
fence tidal systems, including reduced
environmental effects.
• Tidal turbines utilize tidal currents that
are moving with velocities of between 2
and 3 m/s (4 to 6 knots) to generate
between 4 and 13 kW/m2. Fast moving
current (>3 m/s) can cause undue stress
on the blades in a similar way that very
strong gale force winds can damage
traditional wind turbine generators,
whilst lower velocities are uneconomic.

11. Types of Turbines: -
Bulb Type
Rim Type
Tubular Type
•In systems with a bulb turbine, water flows
around the turbine, making access for
maintenance difficult, as the water must be
prevented from flowing past the turbine.
•Rim turbines reduce these problems as the
generator is mounted in the barrage, at right
angles to the turbine blades. Unfortunately, it is
difficult to regulate the performance of these
turbines and it is unsuitable for use in pumping.
•Tubular turbines have been proposed for use
some UK projects. In this configuration, the
blades are connected to a long shaft and
orientated at an angle so that the generator is
sitting on top of the barrage.

12.  Present Tidal Power Plants In world: -
Station Capacity (MW) Country
Annapolis Royal Generating Station 20 Canada
Jiangxia Tidal Power Station 3.2 China
Kislaya Guba Tidal Power Station 1.7 Russia
Rance Tidal Power Station 240 France
Sihwa Lake Tidal Power Station 254 South Korea
Strangford Lough SeaGen 1.2 United Kingdom
Uldolmok Tidal Power Station 1.5 South Korea

13. Environmental Concerns: -
 Tidal power generation can offer significant advantages, including
improved transportation due to the development of traffic or rail bridges
across estuaries and reduced greenhouse gas emissions by utilizing tidal
power in place of fossil fuels.
 However there are also some significant environmental disadvantages
which make tidal power, particularly barrage systems less attractive than
other forms of renewable energy.
 Potentially the largest disadvantage of tidal power is the effect a tidal
station has on the plants and animals which live within the estuary. As
very few tidal barrages have been built, very little is understood about
the full impact of tidal power systems on the local environment. What
has been concluded is that the effect due to a tidal barrage is highly
dependent upon the local geography and marine ecosystem.
 Wales have been caught in tidal generators.
 Fish may move through sluices safely, but when these are closed, fish will
seek out turbines and attempt to swim through them. Also, some fish
will be unable to escape the water speed near a turbine and will be
sucked through.

14. Advantages : -
 Apart from the initial installation cost, tidal power is
free.
 Tidal energy produces no greenhouse gases or any
other kind of pollution.
 It requires no fuel.
 Electricity is produced reliably.
 Not expensive to maintain.
 Tides are totally predictable, enabling us to calculate
when we can generate more, and at times when the
generation is low, shift the load to some other source
of electricity generation.
 Offshore turbines and vertical-axis turbines are not
extremely expensive to build and do not have a large
environmental impact.