How do tidal power plants work

Tidal power plant

Tidal power plants use the potential energy and kinetic energy of the water during ebb and flow to generate electricity. These power plants are built on seas and oceans.

How it works / how it works

Tidal power plants are built in bays and estuaries. Due to the gravitation (force of attraction) of the moon, the water facing the moon is attracted in seas and oceans. Due to the constantly changing position of the moon in relation to the earth, the water is constantly being attracted to a different place by the lunar gravity. Thus it comes to ebb and flow, which bring a water current with them. This water current is used in tidal power plants. Large water turbines are driven by the current and generate electricity via a generator. The turbine can be driven in one direction at high tide and in the other direction at low tide. A large tidal range is advantageous for tidal power plants, as more energy can be converted in this case.

Overview of advantages and disadvantages

Tidal power plants do not produce carbon dioxide (CO2) and are therefore very environmentally friendly. In contrast to hydropower plants / reservoir power plants, they usually do not have such a strong impact on nature because of their presence. However, tidal power plants are dependent on ebb and flow water currents. This results in two disadvantages. They can only be built in certain locations and they often cannot deliver electricity continuously. Low operating costs contrast with high acquisition costs.

Efficiency and further information

At the moment there are tidal power plants with an output range of a few kilowatts up to systems with several 100 MW. Larger power plants of this type have several turbines. The largest tidal power plants can be found in South Korea and France with a capacity of around 250 MW. Most tidal power plants are equipped with Kaplan turbines and achieve an efficiency of up to 90%.