For centuries, mankind has exploited this massive energy source. In the recent years, we have learnt how to generate electricity from it. 450 TWh is the estimated yearly potential of electric power that can be produced from tidal energy. In addition to this comes a large and not yet estimated potential in river flows.
What is Tidal Energy?
Tidal energy or tidal power can be defined as the energy that is the result of the moon and the sun’s gravitaional influence on the ocean. Height differences between high and low tides create tidal currents in coastal areas, and these currents can be strong enough to drive turbines.
Where is Tidal Energy Used?
As tidal power generation is relatively new, there are not a lot of tidal energy companies out there developing investing in this technology yet. However, there are several tidal power plants in use and more is coming. Some of these are solely for research and experimental purposes, but the number of commercial tidal energy power plants is increasing.
La Rance tidal power station was the first large large-scale tide energy project and was opened already in 1966. It lays in the water-rich river Rance in the north-western France. This is a tidal power plant with a total installed capacity of 240 MW capacity generated from 24 turbines. Annual production of electricity is about. 0.6 TWh (600 GWh), which means that the average effect of day throughout the year is 68 MW. La Rance is a form of what we call a tidal barrage power plant.
Tidal Barrage Energy
A tidal barrage power plant consists of three main parts: The first being the barrage itself, holding the water back during high tide. The second part is the sluice gate that let water through the third part, the turbine and generator, resulting in electricity generation.
The sluice gates are left open during high tide and closed during low tide to create a water level differential, creating a potential difference that powers the turbine when the water is released.
Tidal Stream Generator
Tidal stream generators are very similar to wind turbines except their below the water surface instead of above or on land. The turbine and generator converts the movement of water coming from change in tide, the kinetic energy, into electricity. Water is 830 times denser than air and therefore can generate electricity at lower speeds than wind turbines.
Dynamic Tidal Power
Dynamic tidal power is still in the development stage. The theory of this technology is that we can exploit tidal flows and their interaction between potential and kinetic energy.
Advantages of Tidal Energy
There are several advantages with tidal power generation. The greatest benefit after the fact that tidal energy is both a renewable and a green energy source is the incredible potential it posses. The large density of water, almost 1 000 times greater than in air, results in very large amounts of energy to get out of the tidal currents even if the speed is low.
Tidal currents are very predictable, and therefore very favorable with respect to the planning of production and maintenance.
For a full overview over the advantages of tidal energy as well as the disadvantages go to Tidal Energy Pros and Cons.
I hope you learned by reading this article how tidal energy works and realize what big potential these methods of harnessing energy really have. More tidal energy and tidal power facts can be located in the Tidal category.