A PPT on tidal energy technology consisting of the various schemes to harvest the tidal energy, various advantages and disadvantages related to it.

1. TIDAL ENERGY TECHNOLOGY
PRESENTED BY:-
SOUMYA RANJAN DAS
SNEHASIS PANDA
SATYABRATA NAYAK
SITUPARNA SAHU
BADRI NARAYAN SAHU

2. INTRODUCTION TO TIDAL ENERGY
• Demand of electricity is increasing and global
warming also threaten human life. It’s time to
move away from fossil fuel and other source.
• The tides contain energy that can be harnessed to
produce electricity. Two types of tidal energy can
be extracted. Kinetic energy can be harnessed
from the ebbing and surging tides. Potential
energy can be harnessed from differences in the
high and low tides. Using tidal currents remains
the primary method of generating electricity.
• Tidal power has huge potential due to the size of
the oceans and predictability of the tides.

3. WHAT IS TIDE?
• Tides are the rise and fall of the sea levels
caused by the combined effect of the
gravitational forces exerted by the moon and
sun and the rotation of the Earth.
• As the tides come in the level of water on the
beach rises and as the tides goes out the level
of water on the beach goes out.
• Tides are mostly noticeable in oceans and large
lakes.

5. BASIC PHYSICS OF TIDES:-
• Gravitational pull of the sun and moon.
• The pull of the centrifugal force of rotation of
the earth-moon system.
• There are two high tides and low tides during
each period of rotation of the earth.

6. HOW THE TIDES COME AND GO ?
As the Moon and the Earth swing round each other, ocean
water is thrown to the side of the Earth away from the Moon.
At the same time, the moon's gravity attracts water to the side
facing the Moon, resulting in two periods of high tide every
24 hours.

7. TYPES OF TIDES:-
• Tides can be classified on the basis of:-
 Height of the tide:
1. High tide
2. Low tide
 Lunar phase:
1. Spring tide
2. Neap tide

8. HIGH TIDES
• when the sea water reaches its greatest height
within the tide cycle.

9. LOW TIDES
• when the sea water reaches its lowest height
within the tide cycle.

10. SPRING TIDES
• During full or new moons—which occur when the
Earth, sun, and moon are nearly in alignment—average
tidal ranges are slightly larger.
• This occurs twice each month.
• The moon appears new (dark) when it is directly
between the Earth and the sun.
• The moon appears full when the Earth is between the
moon and the sun.
• In both cases, the gravitational pull of the sun is
"added" to the gravitational pull of the moon on Earth,
causing the oceans to bulge a bit more than usual.

11. NEAP TIDES
• Seven days after a spring tide, the sun and moon are
at right angles to each other.
•When this happens, the bulge of the ocean caused by
the sun partially cancels out the bulge of the ocean
caused by the moon
•Neap tides occur during the first and third quarter
moon, when the moon appears "half full."

13. TIDAL ENERGY GENERATION
• The potential energy of the water
contained in the daily movement of the
rising and falling sea levels is utilized to
generate electricity.
• Tidal energy transforms water in motion
into a clean energy.
• Generation of electricity from the
movement of sea water is done by
using water-wheels and turbines.
• The sea water can flow in both directions
in a tidal energy system, hence it can
generate power when the water is
flowing in and also when it is ebbing out.

14. DIFFERENT TYPES OF TIDAL ENERGY
SYSTEMS:
1. Tidal Barrage
 Ebb generation
 Two-basin schemes
2. Tidal lagoon
3. Dynamic tidal power plant

15. TIDAL BARRAGE
 A Tidal Barrage is a type of tidal power generation
that involves the construction of a dam wall, known
as a “barrage” .
 Tidal barrages generate electricity using the
difference in the vertical height between the
incoming high tides and the outgoing low tides.

16. EBB GENERATION
• The basin is filled through the sluices until high tide.
• The turbine gates are kept closed until the sea level
falls to create sufficient head across the barrage, and
then are opened so that the turbines generate until the
head is again low.

17. TWO-BASIN SCHEMES
• With two basins, one is filled at high tide and the
other is emptied at low tide.
• Turbines are placed between the basins.
• Two-basin schemes offer advantages over normal
schemes in that generation time and can be adjusted
with high flexibility and it is also possible to generate
almost continuously.

18. TIDAL LAGOON
• Tidal lagoons work in a similar way to tidal barrages
by capturing a large volume of water behind a man-
made structure which is then released to drive
turbines and generate electricity.
• A tidal lagoon encloses an area of coastline with a
high tidal range behind a breakwater.

19. DYNAMIC TIDAL POWER PLANT
• Dynamic tidal power or DTP is a new and untested method of
tidal power generation. It would involve creating large dam-
like structure extending from the coast straight to the ocean,
with a perpendicular barrier at the far end, forming a large 'T'
shape.
• A single dam can accommodate over 8 GW (8000 MW) of
installed capacity.
• A DTP dam is a long dam of 30 to 60 km which is built
perpendicular to the coast, running straight out into the ocean,
without enclosing an area.
• Other concerns include: shipping routes, marine ecology,
sediments, and storm surges.

20. TIDAL CURRENT TURBINES
• Make use of kinetic energy of moving water to power
turbines, in a similar way to wind turbines that use
wind to power turbines.
• Operate during Flood and Ebb tides.
• Consists of a rotor, gearbox, and a generator. These
three parts are mounted onto a support structure.
• There are three main types structure:
i) Gravity structure
ii) Piled Structure
iii)Floating structure

21. TYPES OF TIDAL CURRENT TURBINES
•Gravity Structures are massive
steel or concrete structures attached to
the base of the units to achieve
stability by their own inertia.
•Piled Structures are pinned to
the seabed by one or more steel or
concrete piles. The piles are fixed to
the seabed by hammering if the
ground conditions are sufficiently soft
or by pre-drilling, positioning and
grouting if the rock is harder.
•Floating Structures provide a
potentially more convincing solution
for deep water locations.

22. SUPPORT STRUCTURE TURBINE

23. TIDAL ENERGY CAN BE CAPTURED
Efficiently and inexpensively using the helical
turbine.

24. FEATURES OF THE HELICAL TURBINE:
BASIC CONCEPT
• designed for hydroelectric
applications in free-
flowing water
• operates in ocean, tidal,
and river currents
• does not require
expensive dams that can
harm the environment

25. FEATURES OF THE HELICAL TURBINE:
OPERATION
• self-starting with flow
as low as 0.6 m/s
• smooth-running
• rotates in same
direction regardless of
the direction of flow,
making it ideal for tidal
applications

26. TIDAL STREAM GENERATORS
• Since tidal stream generators are an immature
technology, no standard technology has yet emerged as
the clear winner.
• but a large variety of designs are being experimented
with, some very close to large scale deployment.

27. MAJOR TWO TYPES OF TIDAL
STREAM GENERATORS
AXIAL TURBINES
• These are close in concept to traditional windmills operating
under the sea.
VERTICAL AND HORIZONTAL AXIS CROSS FLOW
TURBINES
• These turbines that can be deployed either vertically or
horizontally.

28. ADVANTAGES OF USING TIDAL POWER
• Predictable source of “green" energy during lifetime of
barrage
• It produces no greenhouse gases or other waste; it needs no
fuel.
• Not expensive to maintain.
• Tidal energy has an efficiency of 80% in converting the
potential energy of the water into electricity
• Vertical-axis tidal generators may be joined together in
series to create a ‘tidal fence’ capable of generating
electricity on a scale comparable to the largest existing fossil
fuel based, hydroelectric and nuclear energy generation
facilities.
• Provides a non-polluting and inexhaustible supply of
energy.

29. DISADVANTAGES OF USING
TIDAL POWER:
• A barrage across an estuary is very expensive to build, and
affects a very wide area - the environment is changed for many
miles upstream and downstream
• It provides power for around 10 hours each day, when the tide
is actually moving in or out, which is not very much
• Existing ecosystems would be heavily altered, with new
species moving in and perhaps dominating old species
• Tidal power schemes have a high capital cost

30. GLOBAL ENVIRONMENTAL
IMPACT
• A tidal power scheme is a long-term source of electricity. A
proposal for the Severn Barrage, if built, has been projected to
save 18 million tonnes of coal per year of operation. This
decreases the output of greenhouse gases into the atmosphere.
• If fossil fuel resource is likely to decline during the 21st
century, as predicted by Hubbert peak theory, tidal power is
one of the alternative source of energy that will need to be
developed to satisfy the human demand for energy.

32. SIHWA LAKE POWER STATION
• Sihwa Lake Tidal Power
Station is the world's
largest tidal power
installation, with a total
power output capacity of
254 MW.
• This plant opened in 4th
AUG 2011

33. TIDAL PLANTS IN INDIA
• West Bengal Renewable Energy Development
Agency in Sunderbans.
• The Indian state of Gujarat is planning to host
South Asia's first commercial-scale tidal
PowerStation.
• The company Atlantis Resources is to install a
50MW tidal farm in the Gulf of Kutch on India's
west coast, with construction starting early in
2012.
• Later on it is decided to increase the capacity up
to 250MW plants.

34. TIDAL PLANTS IN INDIA
• Situated near the breakwaters of Vizhinjam
Port which is about 20 km from
Thiruvananthapuram city.
• The station started its commercial operation in
1991. This oscillating water column (OWC)
produces about150 kw of power.

35. TIDAL ENEGRY SCENARIO IN
THE WORLD

36. FUTURE OF TIDAL ENERGY
• In a society with increasing energy needs, it is
becoming more and more important to have
alternative sources of power to keep up with
the ever growing energy demand.
• The capacity of tidal energy exceeds that of
coal and oil and is renewable.
• The Department of Energy has shown great
enthusiasm in regards to tidal power as the
perfect energy source for the future.

37. CONCLUSION
• Tidal power is a proven technology and has the
potential to generate significant amounts of
electricity at certain sites around the world.
• Although, our entire electricity needs could
never be met by tidal power alone, it can be
invaluable source of renewable energy.