a green energy source

1. TIDAL ENERGY: A SOURCE
GREEN ENERGY
SUBMITTED BY
MANDVI 1302050
SUKANYA SAHA 1302060
ABHILASHA MITRA 1302060
APAAR 1302086
SEMESTER 7TH
SECTION B
FOR
GREEN ARCHITECTURE
AR. DEBASREETA MISHRA
PILOO MODY COLLEGE OF ARCHITECTURE

2. RENEWABLE & NON CONVENTIONAL
ENERGY SOURCESRenewable energy is generally defined as energy that is collected from resources which
are naturally replenished on a human timescale, such as sunlight, wind, rain, tides, waves,
and geothermal heat.
Renewable energy often provides energy in four important areas: electricity generation,
air and water heating/cooling, transportation, and rural (off-grid) energy services
Non- conventional energy can be defined as the energy sources which are not used as a
source of mass production of energy across the world. For eg. Solar, wind, tidal, geo-
thermal, and many others.
2TIDAL ENERGY: A GREEN ENERGY SOURCE

3. WHAT IS TIDAL ENERGY?
Tidal energy is a form of hydropower that converts the energy of the tides into electricity
or other useful forms of power. The tide is created by the gravitational effect of the sun
and the moon on the earth causing cyclical movement of the seas. Tidal energy is
therefore an entirely predictable form of renewable energy, which can be harnessed in
two forms:
• Tidal Range
Tidal Range is the vertical difference in height between the high tide and the succeeding
low tide.
•Tidal Stream
Tidal Stream is the flow of water as the tide ebbs and floods, and manifests itself as tidal
current.
3TIDAL ENERGY: A GREEN ENERGY SOURCE

4. BASIC PHYSICS OF 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.
4TIDAL ENERGY: A GREEN ENERGY SOURCE

5. TIDAL CURRENTS
• SPRING TIDE: A tide just after a new or full moon, when there is the greatest
difference between high and low water.
High spring tides occur when the sun and the moon line up with the earth. This
occurs when they are either on the same or opposite sides.
• NEAP TIDE: A tide just after the first or third quarters of the moon when there is least
difference between high and low water.
Low neap tides occur when sun and moon line up at 90 ̊ to each other.
Notes:
• FLOOD CURRENTS: Currents moving in the
direction of the coast
• EBB CURRENTS: Currents receeding from
the coast.
5TIDAL ENERGY: A GREEN ENERGY SOURCE

6. TIDAL ENERGY GENERATION METHODS
6TIDAL ENERGY: A GREEN ENERGY SOURCE
• TIDAL STREAM 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 or are
entirely submersed, thus avoiding concerns over impact on the natural landscape.
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 where tidal velocities are greatest.

7. TIDAL ENERGY GENERATION METHODS
7TIDAL ENERGY: A GREEN ENERGY SOURCE
• TIDAL BARRAGE: Tidal barrages make use of the potential energy in the difference in
height (or hydraulic head) 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 channelled 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.
RANCE TIDAL POWER STATION, FRANCE

8. TIDAL ENERGY GENERATION METHODS
8TIDAL ENERGY: A GREEN ENERGY SOURCE
• 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.

9. TIDAL ENERGY GENERATION METHODS
9TIDAL ENERGY: A GREEN ENERGY SOURCE
• 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 pre-existing ecosystem. The lagoons can also be in
double (or triple) format without pumping or with pumping that will flatten out the
power output. The pumping power could be provided by excess to grid demand
renewable energy from for example wind turbines or solar photovoltaic arrays. The
proposed Tidal Lagoon Swansea Bay in Wales, United Kingdom would be the first tidal
power station of this type once built.

10. TIDAL ENERGY USES
10TIDAL ENERGY: A GREEN ENERGY SOURCE
Tidal energy is mainly used for supplying power to the electric power
stations using the same principle of production of Hydro Energy

11. CURRENT SITUATION OF TIDAL ENERGY
• Tidal Energy is sustainable, clean, reliable, widely distributed, and can offer
significant benefits to many marine nations.
• Tidal Energy can be captured in an efficient and cost-effective way.
• Tidal Energy is not yet recognized by the United Nations as an energy resource that
should receive support and funding for its development.
• Technological development in this field is not yet developed enough to produce
efficient mechanisms to produce tidal energy; hence initial installation cost and
maintenance cost is very high.
• Although it is an efficient and green energy source many projects in many
countries are on hold due to their rich marine biodiversity.
11TIDAL ENERGY: A GREEN ENERGY SOURCE

12. POTENTIAL AREAS FOR TIDAL RESOURCES
12TIDAL ENERGY: A GREEN ENERGY SOURCE

13. TIDAL ENERGY PRODUCTION SITUATION IN THE
WORLD
Tidal energy is a very non
conventional source of energy.
Although it can be produced by
many countries with no carbon
footprint; still it is yet to be
popularized because of its high
production cost and technological
shortfalls.
13TIDAL ENERGY: A GREEN ENERGY SOURCE

14. TIDAL ENERGY PRODUCTION STATIONS
14TIDAL ENERGY: A GREEN ENERGY SOURCE
•OPERATIONAL STATIONS
•UNDER CONSTRUCTION
IMAGE REFERENCE: WIKIPEDIA

15. TIDAL ENERGY PRODUCTION STATIONS
15TIDAL ENERGY: A GREEN ENERGY SOURCE
•PROPOSED TIDAL POWER STATIONS
IMAGE REFERENCE: WIKIPEDIA
A tidal power plant has been proposed in Durgaduani of Sundarban, West
Bengal,India but is withheld due to many controversies; of which environmental
impact being the prime concern.

16. ADVANTAGES OF TIDAL ENERGY
16TIDAL ENERGY: A GREEN ENERGY SOURCE
Advantages of Tidal Energy (General)
1) It is an inexhaustible source of energy.
2) Tidal energy is environment friendly energy and doesn't produce greenhouse gases.
3) As 71% of Earth’s surface is covered by water, there is scope to generate this energy
on large scale.
4) We can predict the rise and fall of tides as they follow cyclic fashion.
5) Efficiency of tidal power is far greater as compared to coal, solar or wind energy. Its
efficiency is around 80%.
6) Although cost of construction of tidal power is high but maintenance costs are
relatively low.
7) Tidal Energy doesn’t require any kind of fuel to run.
8) The life of tidal energy power plant is very long.
9) The energy density of tidal energy is relatively higher than other renewable energy
sources.

17. DISADVANTAGES OF TIDAL ENERGY
17TIDAL ENERGY: A GREEN ENERGY SOURCE
Disadvantages of Tidal Barrages
•They change the movement of water into and out of estuaries, which can disrupt the
life cycles of certain marine life.
•They can prevent the movement of fish and other wildlife into and out of estuaries,
which can disrupt spawning.
•Turbines can kill wildlife that tries to swim through them.
•They can increase silt deposits, which can block out sunlight and prevent plants from
growing
•They can change the structure of the coast and lead to erosion of dunes and other
critical habitat
•They prevent access to rivers and cut off shipping
•Costly to build
•Locations are highly limited

18. DISADVANTAGES OF TIDAL ENERGY
18TIDAL ENERGY: A GREEN ENERGY SOURCE
Disadvantages of Tidal Stream Generators
•Spinning blades can kill marine wildlife
•Acoustic disturbances can affect migration and other aspects of marine life
•They can change the movement and rise of tides
•They can interfere with shipping channels
•They are more prone to damage by high waves and rough water than other systems
Disadvantages of Dynamic Tidal Power Schemes
•They are very costly
•They are untested and therefore their usefulness and environmental impacts are
unknown
•They can disrupt migration of marine life
•They can change coastal structures in unpredictable ways

19. DISADVANTAGES OF TIDAL ENERGY
19TIDAL ENERGY: A GREEN ENERGY SOURCE
GENERAL
1) Cost of construction of tidal power plant is high.
2) There are very few ideal locations for construction of plant and they too are localized
to coastal regions only.
3) Intensity of sea waves is unpredictable and there can be damage to power
generation units.
4) Influences aquatic life adversely and can disrupt migration of fish.
5) The actual generation is for a short period of time. The tides only happen twice a day
so electricity can be produced only for that time.
6) Frozen sea, low or weak tides, straight shorelines, low tidal rise or fall are some of
the obstructions.
7) This technology is still not cost effective and more technological advancements are
required to make it commercially viable.
8) Usually the places where tidal energy is produced are far away from the places
where it is consumed. This transmission is expensive and difficult.

20. REFERENCES
20TIDAL ENERGY: A GREEN ENERGY SOURCE
•Wikipedia.org
•Study.com
•Tidal energy ltd.