3. LAND
SEA
BASIN
S
E
M
E
M
Spring tides Neap tides
BARRAGE
Tides are formed because of
gravitational forces between sun,
moon and earth
Waves form because of force of wind on
surface water of sea
Types of Tides
High and Low Tides
Spring and Neap tides
6. Tidal energy is produced by the surge of ocean waters during the rise and fall of tides.It is
generated by the combined effects of the gravitational force of the moon and the sun
and the rotation of the earth.
Tides contain large amount of potential energy which is used for power generation.
When the water is above the mean sea level, it is called flood tide. When the water level
is below the mean level it is called ebb tide.
Barrages can be constructed across tidal rivers, bays, and estuaries. Turbines inside the
barrage harness the power of tides the same way a river dam harnesses the power of a
river. The barrage gates are open as the tide rises. At high tide, the barrage gates close,
creating a pool, or tidal lagoon. The water is then released through the barrage's
turbines, creating energy at a rate that can be controlled by engineers.
7. The followings are the components of a tidal power plants.
1. The dam to form the pool or basin.
2. Sluice ways from the basins to the sea.
3. The power house.
Dam – The function of dam is to form a barrier between the sea and the basin.
Sluice ways – These are used to fill the basin during the high tide or empty the basin
during the low tide, as per operational requirement.
Power house – It consists of turbines, electric generators and other auxiliary
equipments.
8. Tidal power plants are classified into
Single basin arrangement
a) Single tide – cycle system
b) Double cycle system
c) Single ebb – cycle system
Double basin arrangement
Single ebb cycle system
The single basin schemes have only one basin. Power generation is intermittent and
mostly during off-peak load periods on daily load curves. The tidal basin and the sea
are separated by a dam or dyke. The rise and fall of tidal water levels provide the
potential head.
When the sea level raises, the sluice gates are opened and the sea water flows into
the basin. The basin level then stays constant while the tide continues to go out. The
turbine values are opened after getting sufficient water head, the water now flows
from basin to the sea thereby generating power.
