Wave energy is captured directly from surface waves or from different pressure fluctuations between the surfaces. This energy can then be used to power a turbine and the simple and mostly used working principle of this procedure would be as follows: First the wave raises into a chamber and then the rising water forces the air out of the chamber and the moving air spins a turbine which then turns a generator. The main problem with wave energy is the fact that this energy source isn't the same in all parts of the world, since it varies significantly from place to place. This is the reason why wave energy can't be exploited in all parts of the world but there are many researches that work on solutions of how to solve this variability problem. However, there are still many rich wave power areas in the world like the western coasts of Scotland, northern Canada, southern Africa, Australia, and the northwestern coasts of the United States, all with high potential for wave power exploitation. There are many different technologies to capture wave power but very few of these technologies is commercial enough to be fully used. Wave technologies are not only installed near shore and offshore but already also in far offshore locations and the emphasis of new research projects such as “The OCS Alternative Energy Programmatic EIS” is particularly on offshore and far offshore wave technologies where offshore systems are located in deep water, on depths passing even 40 meters. Majority of wave energy technologies are still oriented to installations at or near the water surface, and the main difference between these technologies is their orientation to the waves with which they are interacting with and in their working principle in which they convert the energy of the waves into desired energy forms. Among most popular wave energy technologies are terminator devices, point absorbers, attenuators, and overtopping devices. Terminator devices such as oscillating water column are typically onshore or near shore and have working principle that extend perpendicular to the direction of wave travel and capture or reflect the power of the wave and then the captured water column moves up and down like a piston, forcing the air through an opening connected to a turbine. Point absorbers are different type of wave technology that involves floating structures with components that move relative to each other because of wave action and energy gets produced as this movement drives electromechanical or hydraulic energy converters. Attenuators are also floating structures that are oriented parallel to the direction of the waves and where differing heights of waves along the length of the device causes flexing on the place where the segments connect, and this flexing is connected to hydraulic pumps or other converters for its transformation to energy. Overtopping devices have different working principle and they are basically reservoirs filled by incoming waves to levels above the average surrounding ocean, and after the water gets released gravity causes it to fall back toward the ocean surface and this energy of falling water is then used to turn hydro turbines. While there is definitely undisputed high potential of wave energy there are certain aspects that also need to be considered such as environmental problems as these technologies can influence marine habitat as there is potential danger of toxic releases into sea in form of hydraulic fluids, noise generation above and below water surface, changes in the seafloor, etc. Wave Energy as a Global Energy Resource Wave energy is a renewable energy resource created by large storms hundreds of kilometers offshore that generate and transmit huge amounts of energy that travels great distances (via swell) and mixes with local influences (seas) to arrive at our shores. It is a genuinely renewable energy source and distinct from tidal energy. Wave energy is generally considered to be the most concentrated and least variable form of renewable energy. It is the high power density of wave energy that suggests it has the capacity to become the lowest cost renewable energy source. The World Energy Council has estimated that approximately 2 terawatts (2 million megawatts), about double current world electricity production, could be produced from the oceans via wave power. It is estimated that 1 million gigawatt hours of wave energy hits Australian shores annually and that 25% of the UK's current power usage could be supplied by harvesting its wave resource. Wave energy has significant global potential with the USA, North & South America, Western Europe, Japan, South Africa, Australia and New Zealand among some of the best wave energy sites around the world. Wave energy flows in the direction of wave propagation and is measured as the amount of power (in kW) contained in each linear metre of wave front. Typically energy above 20kW/m may be suitable for CETO wave farm projects. |
