Ocean waves are caused by the wind blowing over the surface of the ocean, and in some areas of the world these winds are both consistent enough, as well as powerful enough to provide continuous big waves. Big ocean waves are tremendous source of energy and extracting useful energy from big ocean waves has great potential to become significant source of renewable energy in some parts of the world in years to come.
The main disadvantage of wave power is the fact that wave power varies considerably in different parts of the world meaning that not all parts of the world have required efficiency to make wave energy projects economically viable. The areas with great wave energy potential include western coasts of Scotland, northern Canada, southern Africa, Australia, and the northwestern coasts of the United States. In order for wave energy projects to be commercially viable a suitable site, where waves are consistently strong is needed.
Also, wave energy projects are still not widely employed technology, and wave energy technology is currently in infant phase of its growth, despite the presence of world's first commercial wave farm based in Portugal, at the Aguçadoura Wave Park.
Since wave energy projects require locations where waves are consistently strong they have to be very powerfully built to withstand very rough weather conditions, and such projects are therefore in most cases costly to develop.
Harnessing wave energy can have some negative effects from the environmental point of view such as disturbing or disrupting marine life or having some negative visual and noise impacts.
When we talk about the advantages of wave power then the first thing we should mention is that wave energy is renewable energy source with completely free energy where no fuel is needed and there is no problem with emissions and/or waste like with some other energy sources.
Wave power has very big potential, and can produce more than significant amount of energy (the useful deep water wave power resources have been estimated to be greater than 2 TW). Also, once wave energy projects are built they are not very expensive to operate and maintain.
Wave power also has advantage in its predictability. Many people do not know that waves are very predictable. The waves that are caused by winds can be predicted five days in advance.
Also new wave energy projects would also provide many job opportunities in construction, operations and maintenance.
With further development in technology I wouldn't be surprised if wave energy in future becomes one of the most important renewable energy sources.