How Does Tidal Power Work?

Tidal Energy is the movement of waves or tides due to the gravitational attraction of the Earth and the moon. Moreover, it is environmentally friendly energy and doesn’t produce pollution or greenhouse gases.

What is Tidal Energy?

Tidal Energy is another form of hydropower that utilizes large amounts of energy within the tides of the ocean to generate electricity. Tidal Energy is an alternative source of energy that can also be considered as renewable energy.

Therefore, tidal energy or tidal power can be defined as the energy that is the result of the sun and the moon’s gravitational force on the ocean. It is just that the differences between high and low tides create tidal currents in coastal areas, and these currents are enough to drive the turbines.

Tidal energy is the energy obtained from changing sea levels, which moves from high to low and vice versa. This clean, renewable energy source has excellent potential to work as tides are much more predictable than solar power or wind energy, which are not at all consistent.

Tidal energy requires a significant capital investment in dams, turbines, and support ships. Still, once a “tidal power” plant is built, the energy it generates is mostly free, with the system being relatively inexpensive to run.

The world’s biggest tidal energy generator is being placed off the coast of Invergordon, Scotland. The new tidal generator in Scotland is big. The turbine blades are 18 meters across. It weighs 143 tons and stands 22.5 meters high. It is capable of generating enough electricity to power more than 1,000 homes.

Unlike the wind, the tides are very predictable. So it’s easy to decide where to put tidal turbines and figure out how much energy they will generate. Additionally, the turbines are usually entirely underwater, so no one can complain about them spoiling the view!

How does Tide Works?

We are aware that there are high tides and low tides in the ocean. The water rises and falls twice a day. For the most part, this rise and fall are only noticeable for reasonably large bodies of water.

There are mainly two gravitational influences on our planet. One is the sun, and the other is the moon, which orbits around the Earth, much as the Earth orbits around the sun. Though the sun’s gravity is much powerful, its distance from the Earth means it has much less effect on our planet than the moon.

The sun is approximately 149,600,000 kilometers away from the Earth, whereas the moon is about 384,400 kilometers away from the Earth. As gravity varies with the square of the distance, it certainly drops off very quickly as one moves away from the source.

As a result, the effect of the sun on the tides is less substantial than the effect of the moon. In fact, the sun has about a 49% gravity effect than the force of gravity from the moon.

The water never has a chance to capture and flow to the moon side of the Earth because the moon is continuously moving, and the Earth is also continually spinning. The result is two high tides every day spaced about 12 hours and 25 minutes apart.  When the moon is overhead, its tide occurs higher than it occurs when the moon is on the opposite side of the planet. While understanding how tidal energy works, it is also necessary to learn the pros and cons of tidal energy which we have presented in our ‘Tidal Energy: Pros and Cons Article‘.

3 Major Parts of a Tidal Power Plant

Tidal Barrage

A tidal barrage resembles a dam structure that is used to catch up the energy from a large amount of water moving in and out of a bay due to tidal forces. Though the barrage resembles a dam, it is a lot bigger and also constructed across a Bay or an Estuary.

It is also considered as the most efficient tidal energy technology. The most simple generation system for tidal plants involves a dam that is also known as a barrage.

A tidal barrage is a barrier built over a river estuary to make use of the kinetic energy in the moving water. The barrage contains electricity generators, which are driven by the water rushing through tubes in the barrage. This produces energy similar to a dammed river, where the water level is higher on one side of a tidal barrier than it is on the other side.

Sluice Gate

Sluice gates are the main part of the tidal power plant that allows water to flow through the turbines and generate electricity. It also allows the tidal basin to fill on the incoming high and low tides and to empty through the turbine on the outgoing tide.

When each time water passes through the barrage, the turbine spins and electricity is generated. As a result of the tidal cycles, there are four main times during each day that power is produced most effectively during incoming and outgoing tides.

The sluice gates are opened during high tide and closed during low tide to create a balance in the water level and also creates a potential difference that powers the turbine when the water is released.

Thus, the tidal power plant is a marine renewable energy generation system that uses dams, long walls, sluice gates, and tidal locks to capture and store the potential energy of the ocean.

Tidal Turbines

The turbines that are used for wind power plants are almost similar. The only difference is that the blades of tidal turbines are much stronger and shorter. So, the best way to compare tidal turbines is underwater windmills. Further, water is 830 times denser than air and can generate electricity at lower speeds than wind turbines.

Ideally, the water currents turn the turbine. The turbine is connected to a generator through a shaft.  So, when the turbine spins, the shaft also turns. The turning shaft activates a generator, which generates electricity.

It is a fact that the cost of these tidal stream systems are very expensive and also required a high cost for the installation and maintenance. However, it remains a cheaper alternative and doesn’t cause any pollution or environmental degradation in comparison with other tidal technologies.


Although tidal power is not widely used all over the world, it has a high potential for future electricity generation. It is more reliable and predictable than solar energy and wind energy. Though it is easily available in plenty of harnessing energy from but not that much easy to build. It requires a huge investment and limits the availability of sites where it can be captured.

With increasing energy needs each day in the world, it has become more important to have alternative sources of energy to keep up with the rapidly growing energy demand. The capacity of tidal power exceeds that of fossil fuels, and most importantly, it is renewable and clean.