Perhaps you have wondered, while lying on the beach or in a boat and feeling the strong pull of the waves or tides, whether it would be possible to harness all that power to produce electricity, just as we do with other elements of nature. This idea is hardly original: the first patent for wave energy was presented in France in 1799, although it was not until the early 70's of the previous century that the idea gave rise to projects funded by companies and governments like Japan and the UK.
However, the slow development of technology and the enormous costs were crippling some projects that have resurfaced in the last five years. More and more governments and companies are beginning to invest in this type of energy, aware that renewable energies may be the key in helping to avoid problems such as pollution and the scarcity of energy resources, and supported by technological advances. The European Union, where the Atlantic Ocean, the North Sea and the waters surrounding the Scandinavian countries have ideal conditions, is also taking the lead in these types of projects. In fact, the Scottish island of Islay boasts the first European turbine that works with wave motion to generate power for 400 homes.
Currently, there are a dozen ways to obtain electricity from wave motion at different stages of development, and with no certainty as to which may become the final one. Basically, they can be divided into two types. On the one hand, those that take advantage of the horizontal movement of the waves and that follow the same principle used in hydroelectricity: channelling the waves through structures of pipes that carry water to a tank located on land, which feeds a system of turbines that generates electric power. In the other group we can find methods based on the vertical oscillations of the waves. The energy of the tides is converted into electricity in tidal power stations, which operate like a traditional river reservoir. The tank becomes filled with the tide and the water is retained until low tide to be released later through a network of narrow channels increasing the pressure until it reaches the turbines that generate electricity. The problem is that high maintenance costs slow their proliferation.
Despite these promising projects, the energy from the sea is still far from being a useful reality. WaveNet network created by the European Commission in 2000 and composed of academics, industries and research institutes from European countries, published a study explaining that the lack of public knowledge is one of the obstacles that hinder its development. The report detailed also some negative consequences that might arise in energy production, such as noise, risk of collision with ships, visual impact and possible changes in the structure of the water sediments. Consequently, the study highlighted the need for further research in order to make these technologies more competitive.
WAVE FORCES ON PILES IN RELATION TO WAVE ENERGY SPECTRA