What is Tidal energy?


Tidal Energy History

Most people don’t aware about the first tidal mill was invented in the year 618-619. But it is not used for electricity generation. Till the end of the 18th century, only in London, around 76 tidal mills were used. There was a time in the Atlantic Ocean around 750 tidal mills in operation. Out of that, 200 in the British Isles, 300 in North American shore & 100 in France. France is the home of tidal energy. In 1966, on the river of the Rance, the first tidal power plant was established. It is the world’s first tidal power plant.

What is tidal energy & how it works?

Tidal energy is the process of converting tide energy into electricity or any other useful form. Tides are generated in the ocean because of the gravitational force of the moon, sun & motion of the earth.

Due to these reasons, high tide & low tides get generated. In this tidal power generation process, the power of these tides is used to drive the rotor to generates electricity.

Methods for harnessing tidal energy

Tidal steam generator

Tidal stream generator follows the same principle used in the wind turbine. In a wind turbine, the kinetic energy of the wind is used to drive the rotor of the windmill.

Instead of the wind, the kinetic energy of the water is used to drive the turbines in the tidal steam generator.

These generators are fully submerged in the water. It also builds on the structures of the existing bridges. The rotor of these generators is mounted on the vertical platform, which is partially submerged in the water.

The flow of the water over the turbine helps to harness tidal energy.

Tidal barrage

Tidal barrage uses the energy of the tides generated during the high tide & low tides. These tides are due to the gravitational force of the sun & moon.

In between the sluice gates turbines are placed to generate electricity. During the high tide, water flows into the sluice gates through the turbine & during low tide it gets reverse.

Due to the kinetic motion of the water, the turbine rotates & tidal energy is harnessed to generate electricity.

Dynamic tidal power

Dynamic tidal power is the theoretical concept that can use the potential & kinetic energy of the tidal to generate electricity.

Tidal lagoon

The tidal lagoon process is similar to the tidal barrage. But the only difference is that it creates an artificial lagoon to store water to generate heat during the high tide.

Once sufficient heat is generated in the lagoon, then it is passed through the turbine placed between sluice gates.

Due to that turbine rotates & electrical energy is generated. This process is repeated during the ebb tides to harness tidal energy.

Is Tidal energy renewable?

Ocean or sea is a renewable source of energy. The tides are developed due to the gravitational force of the moon & sun with the rotational motion of the earth. These tides are used to generate electricity. So tidal energy is a renewable energy source.

Top Tidal energy power plants

1. Sihwa Lake Tidal Power Plant (Country-South Korea)

Sihwa Lake Tidal Power Plant is located 4 kilometers away from Siheung city. Electricity is generated with this power plant using a bulb turbine (submerged). The output capacity of this tidal power plant is 254 MW.  

2. La Rance Tidal Power Plant (Country-France)

La Rance tidal power plant is located on the river of the Rance. This power plant is in operation since 1966. 240MW is the output capacity of this power plant. 

3. Swansea Bay Tidal Lagoon power plant (Country-United Kingdom)

It is the third biggest tidal power plant. The output capacity of this power plant is 240MW.

Tidal energy efficiency

The efficiency of the tidal power depends on the tide flow & the design of the blade. At a speed of 2.5 m/s efficiency of deformed, pre-deformed & rigid blade varies from 45.5 % to 47.6 %.

Advantages of tidal energy

It is a renewable source of energy.

The design life of the tidal power plants is more as compare to other renewable energy plants.

It is a consistent source of energy due to the known time of the tides.

 Disadvantages of tidal energy

It can affect the life of the ocean animals due to sound created during the rotation of the blades. There are chances of getting killed by ocean animals due to rotating blades. Sometimes high frequency & amplitude causes a bad impact on marine lives.

Construction cost is high. The cost required for generating the same electricity generated by wind energy or solar energy is high.

Cyclones or heavy tides like tsunami can destroy all the structures.

Leakage of lubricating oils, greases & & other oils can harm marine life.

Future of tidal energy

On the earth 71% is water and out of that most of it is covered by the ocean. So the ocean is a huge source of the energy. Nowadays the use of tidal power is increasing.

In the future, due to more advanced technology & increased efficiency of the tidal power plants. Due to that, us of it will increase. Also due to inventions in the tidal power plants, its cost will get reduced.

Some of the countries like the UK, France, South Korea are working to develop more advanced turbines that can harness most of the tidal power.

The use of renewable sources of energy is the need of the future instead of non-renewable sources of energy.


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