Tidal energy harnesses the potential and kinetic energy of tides. It is caused by gravitational forces from the moon and sun. There are two types of tides - spring and neap. Tidal energy can be extracted via tidal barrages or tidal stream generators. India has significant tidal energy potential, especially along its western and eastern coasts. While tidal energy is renewable and predictable, the initial costs are high and locations suitable for tidal projects are limited. It is seen as an important future energy source due to its large capacity and renewable nature.

1. Renewable Energy Sources

2. Introduction
The global energy requirements are primarily provided by 80 percent of the
total demanding energy is furnished by sources such as natural gas, coal,
which are quickly being depleted as well as being environmentally
unfriendly.
We are looking for renewable resources to substitute current ones is
much urgent for us.
Tidal power is classified as a renewable energy source.
What is Tidal Energy?
• This is the only form of energy whose source is the moon.
• It is a renewable energy source because Tides are the waves caused
due to the gravitational pull of the moon and sun (though its pull is
very low) on water (world’s oceans) and also by the rotation of the
earth.
• Due to these gravitational forces the water level follows a periodic
high and low.
There are two types of tide
• Spring tide: When the sun and the moon are in line, their
gravitational forces are combined together.
• Neap tide: When the moon and the sun are located at 90◦ angle to
each other, their gravitational force pulls the water in different
directions, causing the bulges to eliminate each other’s effect.
• The period between the two spring tides or neap tides is around 14
days, half of the lunar cycle.
Types of Tidal Energy
There are two types of energy systems that can be used to extracted
energy
Kinetic energy: from the moving water of rivers, tides and open ocean
currents.
Potential energy: from the difference in height (or head) between high
and low tides.

3. Tidal energy potential (Energy scenario)
Indian context:
Total identified potential: about 9000 MW.
• West Coast
o Gulf of Cambay (7000 MW)
o Gulf of Kutch (1200 MW)
• East Coast
o The Ganges Delta in Sunderbans in West Bengal (100 MW)
World’s leader:
• France has the largest (Rance) tidal power station in the world and
largest tidal barrage power plant also. It is constructed between 1961
and 1967 and situated on the Rance River. It generates a capacity of
240MW and a net power output of 480GWh per year.
• Severn Barrage at Bristol Channel in UK. it colossal of power plant of
8,560 mw of installed capacity with an average annual generation of
17Gwh.
Where is Tidal Power used in world?
• Canada
• U.S.A.
• Chile
• France
• U.K.
• China
• India
• Japan
• Korea
• Norway
• Australia
• Russian Federation

4. Economics
• Tidal energy is not cost competitive because it is generally not
commercially available.
• When selecting a spot to set up a tidal energy station it is important to
make sure that it will be economically feasible.
• To set up a tidal facility with an average annual output of 2,200MW
would cost about 3 billion dollars, not including maintenance and
running costs.
• This is far more expensive than coal and oil.
Energy Source Cost Comparisons in U.S.A
• National average cost of Electricity 8.83 cents per kilowatt hour.
• Total cost for energy generation for coal, Nuclear, Natural Gas, Solar,
Wind Power, Free-Flow Tidal Current and Submerged Tidal Array as
10.29, 3.31, 8.09, 18.12, 3.45, 7 – 10 and 6.5 - 8.5 cents per kilowatt
hour respectively. No Indirect social costs for tidal power.

5. Generating methods of Tidal Power
Reference:http://www.ei.lehigh.edu/learners/energy/tidal/tidal5.html
Tidal Barrage:
Tidal barrages make use of the potential energy in the difference in height
(or head) between high and low tides.
• Water flows over the barrage and fill the tidal basin during high tides.
• The sluice gates will open and let the water flow out to the ocean during
low tides.
• The flowing water moves the turbines and creates electricity.

6. Tidal stream generator:
It makes use of the kinetic energy of moving water to power turbines. Tidal
Currents move through the turbine. Turbine powers the generator and
create electricity. Do not require a dam like tidal barrages.
Dynamic Tidal Power:
The theory of this technology is that we can exploit tidal flows and their
interaction between potential and kinetic energy.
Uses of Tidal Renewable Energy
• Tidal electricity: The main usage of Tidal Energy is in the generation
of Electricity.
• Grain mills: Tidal Energy was used for the mechanical crushing of
grains in Grain Mills.
• Energy storage: Tidal Barrages with their reservoirs can be modified
to store energy.
• Provide protection to coast in high storms: Tidal Barrages can
prevent Damage to the Coast during High Storms.
Advantages
• Renewable, non-Polluting and Carbon Negative
• Predictable
• No fuel
• Improved transportation because of the development of traffic or rail
bridges across estuaries
• It is a reliable, dependable source

7. Disadvantages
• High initial construction costs.
• Limited locations around the World where tidal energy is viable.
• Habitat and environmental changes and destruction particular with
tidal barrages.
• Transmission of power hampered by power generation necessarily
being located near oceans
Future?
• 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.
• It is the perfect energy source for the future according to DOE.