RENEWABLE ENERGIES: Wave power

WAVE POWER: (still experimental)

The kinetic energy produced by the movement of the device thanks to the waves is converted into electricity.
The technology is new and developing, the operating environment is severe and the maintenance and repair costs can be very high. The electricity produced is small and intermittent and the commercial viability is not proven yet.
The kinetic energy produced by the movement of the device thanks to the waves is converted into electricity. The technology is new and developing, the operating environment is severe and the maintenance and repair costs can be very high. The electricity produced is small and intermittent and the commercial viability is not proven yet.

(Picture from “Technical English”, Pearson, Longman)

In the first device, the wave energy converter, the oscillating waves make a flexible disc move up and down. The disc is attached to a large lever: this makes two pistons move up and down. This sucks sea water into a chamber and then through pipes at high pressure to drive a turbine, which generates electricity.

(Pictures from “Technical English”, Pearson, Longman)

The second device, the wave energy buoy, has an electric coil attached to its interior. Freely moving inside the coil is a magnetic shaft, connected to the sea bed. When the buoy moves on the sea, the coil moves over the shaft, generating electricity in the coil. The electricity is transferred from the buoy to an electricity grid on the sea bed, and fed to the shore.

The third device, the wave power station contains a turbine and generator. The waves push water into a lower chamber, which forces air through a valve into an upper chamber, which contains the turbine. The motion of the air turns the turbine and generates electricity.

In the fourth device, the wave roller, the waves push metal plates forwards and backwards. This movement operates a hydraulic piston pump, which forces oil along a pipe and powers a turbine on land.

Pelamis-Wave-Power

The fifth device, the Pelamis, operates in water depths greater than 50m and is typically installed 2-10 km from the coast. The machine is made up of five tube sections linked by universal joints, which allow flexing in two directions. It floats semi-submerged on the surface of the water.

Operating principle of Pelamis

When the waves pass on the machine, the sections oscillate in the water and the movement is converted into electricity by hydraulic power systems housed inside each joint of the machine tubes. Power is transmitted to shore using standard sub-sea cables and equipment.