Wave power plants use the kinetic energy of the moving waves. The movement of the waves is caused by the wind.

About 200 years ago, the first machines for using the wave energy were developed. These single low power machines have been developed into wave power plants.

There are different ways of using wave power. Two machine types are explained below.

The first machine type is the so called "Salter-Duck" (invented in 1973 by Stephen H. Salter).

The "Salter-Duck" consists of a series of such cams. The cams are located on the surface of the water. The waves push on the cams and the cams oscillate.

The movement of the cams drives special pumps. Liquid, like water or oil, is pumped in the same way with high pressure. Electrical energy is generated by hydraulic motors using the high pressure of the liquid.

Another way of converting wave energy is the "Wave-converter" (by J.Masuda).

During the falling wave there is a vacuum in both chambers. The left valve opens and air is sucked through the left valve. In order to get into the right chamber the air has to pass the propeller. The propeller rotates and drives the generator.

During the rising wave the air is compressed. The left valve closes and the right valve opens. The air from the left air chamber has to pass the propeller. The air flow drives the propeller and the generator transforms the rotation into electricity.