Outlook for wave energy technology
Wave energy is the power that is transferred by the waves at the ocean’s surface. Waves are created by the wind blowing over the sea surface. An energy transfer between the waves and the wind takes place, if the waves move slower than the wind. The height of a wave is conditioned by wind velocity, the period of time when the wind has been blowing, the distance over which it has raised the waves and by seafloor topography.
Wave energy can be harnessed to fulfil useful work, for example, to generate electricity, to desalinate water or to pump it into reservoirs. At present wave energy technology is not widely used, however, there have been some successful attempts to employ it since the end of 19th century.
Wave power farms
Power farms are sets of special wave power machines that are implemented to generate electricity. The year 2008 was marked by the opening of the first wave power farm in Portugal. This farm was opened in November and it employed three energy converters for production of electric power. However, because of certain technical problems it was closed down just after a couple of months of its operation.
In 2007 the United Kingdom set aside some funds for the development of the Marine Power farm near Scotland and the Wave hub near Cornwall. Those farms will allow to operate the devices generating wave energy and to keep the costs low.
Advantages of wave energy
- this form of energy, which is yet to be harnessed by mankind, has an immense potential; it is renewable and clean;
- wave energy is potentially one of the most environmentally friendly forms of electrical power generation;
- ocean wave energy can be easily predicted with 5-day accuracy;
- wave energy can play a big role in combating climate change by displacing CO2 from fossil fuel sources;
- implementation of wave power can provide employment in construction, maintenance and operation of the installations used.
Various wave energy technologies
A range of technologies has been brought forward by the developers in order to capture wave energy. A number of such technologies that have long-term prospects are currently being tested commercially.
Wave energy systems can be installed either far offshore, offshore or nearshore. Despite the fact that all of them are meant to be placed at the water’s surface or close to it, they are different in their orientation and in the way they convert wave energy. Here are some of the technologies that have been the focus of present development.
The terminator devices are usually placed nearshore (though offshore floating ones have also been developed), perpendicularly to the waves’ direction and they trap or reflect wave energy. The oscillating water column (OWC) is an example of a terminator device using moving water and air in order to turn a turbine at the top of the column.
Another wave energy technology to be mentioned is a point absorber – a structure that floats and absorbs energy near the surface owing to its movements. Attenuator is a long device, which floats parallel to the waves. Different wave heights cause flexing in places where the parts of the device are connected, and, in its turn, this flexing sets pumps or some other converters in motion.
There are also overtopping devices that have special reservoirs towering above the surrounding water surface. These reservoirs get filled up by the waves, after that the water is released and due to gravity it falls back into the ocean. The falling water energy is usually exploited to turn hydro turbines. Seagoing vessel is a wave energy technology that uses a floating platform, which generates electrical power by funnelling water through turbines and after that releasing it.
It is true that wave power differs greatly from location to location and, therefore, cannot be captured everywhere. The areas that are rich in wave power are coasts of Scotland, Africa, United States, Canada, and Australia.
