Types

• Oscillating water column: uses a large volume of moving water as a piston in a cylinder. Air is forced out of the column as the water rises and fresh air comes in when the water falls. These movements of the air turn a weir turbine at the top of the column. This is used for industrial sized wave stations.
• Buoyant moored device: A device that floats on the water and is anchored to the sea floor. The tension between the waves and the mooring creates the power.
• Hinged Contour Device: is loosely moored to the sea bed. In general, as the waves move up and down, parts of the device move in motion. The tension between the different parts creates the power.

How it works?

There are several methods of getting energy from the waves, but the manufactured and industrial method works rather simply compared to other energies. The oscillating water column method is used; the Islay wave power generator is an example. Refer to the diagram on the right for visual representation. It consists of two basic elements; a wave energy collector and a generator to turn this into electricity. A sloping reinforced shell is built into the rock face on the shoreline. It contains an inlet big enough for the waves to enter the chamber freely and leave just the same. As the waves enter the chamber, the level of water rises, compressing the air in the chamber towards the top. The air is then forced through a "blowhole" and towards the turbine. The turbine is designed to turn the same way, irrespective to the direction of the airflow. As the water leaves the chamber, the air is drawn back into the chamber, under pressure, keeping the turbine moving. The constant streams of air in both directions, caused by the oscillating water column, makes the turbine move, to drive a generator, which converts the energy into electricity. It is then distributed by the local electricity distribution site. 

Advantages & Disadvantages

Advantages

• The energy is free, no fuel needed, no waste produced
• Does not produce greenhouse gases
• Very few safety risks
• Not expensive to operate, the cost is in building the power station
• Can produce a great deal of energy
• IT IS RENEWABLE!
  

Disadvantages

• Waves decide everything, big waves, loads of energy, small waves, no energy
• Waves must be consistent in the site
• Transporting the electricity from the sea to the land
• Some designs are noisy
• Needs to withstand very rough weather
• Natural beauty of an area is spoiled