PDF | Oceans are the largest collector of solar energy on the earth's surface. Considering oceans cover more than 70% of the earth's surface, the amount of. PDF | Ocean energy is an important and promising renewable energy for the future. Even though extensive technology development and. OCEAN ENERGY TECHNOLOGIES for RENEWABLE ENERGY GENERATION. AUGUST Peter Meisen. President, Global Energy Network Institute (GENI).
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ocean energy (wave and tidal energy), presents the EU with an opportunity to generate 13ruthenpress.info The main forms of ocean energy are waves, tides, Ocean thermal energy conversion (OTEC) uses the .. gic%20Technology%ruthenpress.info 5. Fact file. Ocean Energy Systems (OES), also known as the Technology Collaboration Programme Ocean Renewable Energy in Southeast Asia – Opportunities and.
They are dwarfed by the 52 turbine wind farm of Hadyard Hills South Ayrshire.
Thus far MW of electricity generating wind turbines came on line in , providing current for 80, household and over MW were added to normal electricity production.
Production costs vary of course with the speed of 31 Formerly Zuiderzee, prior to the damming and polderization of a major portion of the water body. This figure may have to be scaled down, however, as a study conducted in on behalf of the European Union; indeed, there are several sites where turbines cannot be placed, for instance because depths are too great or the distance to shore is. The same rather simplistic calculation ventured of the possibility that the British could capture at sea four times their electricity needs, the Irish fourteen and the Danes even seventeen.
At Zeebrugge, Belgium, a small park has been installed on the sea harbor breakwaters. Production amounts to 4. Belgian authorities gave recently the green light for positioning fifty air turbines on an artificial island at 15 km 8. The 1, MW produced are to provide electricity to 85, families. Construction is scheduled to start in and placing into service in Notwithstanding reports from similar projects concluding to benign influence on the marine environment, an impact study will be conducted.
The installation is deemed to have a life span of 20 years and the contractors are held, by the contract, to remove all wastes. Coming from a city that has, for many years, notoriously failed to provide adequate water purification facilities, one may raise a somewhat surprised eyebrow.
Granted, the marine wind parks are not exactly attractive, yet they are not really objectionable, the more so that they are visible at best as specks on the horizon. The endless procedures came finally to a close in and the wind-park will be built. The delay has had one advantage: technology has progressed and the latest and largest turbines will be installed.
Its wings spread about 15 m. The government promised that by the energy used in the country would be generated by sustainable sources.
Wind power from the ocean has also been considered for providing the energy needed by pumps and desalination plants.
Marine winds are providing energy to 24 turbines in Zeebrugge; they have a total capacity of 5. This would, however, require placing , 2-MW turbines in North Sea sites. Such projects, understandably, distress tourism-conscious resort municipalities such as Knokke-Heist and Wenduine-Klemskerke-De Haan.
Probably the first to be taken out was by Girard, father and son in and proposed to take out mechanical energy using a raft. In the twentieth century buoys and lighthouses used wave-generated electricity. The power is provided by the onslaught of a breaking wave, which can be captured in a reservoir, accessible by way of a converging ramp, and connected with a return channel at the exit of a low pressure turbine.
Power can also be generated by means of devices set directly in motion by the wave itself. Summed up the total available power of ocean wind waves amounts to 2. Waves are a concentrated form of wind energy.
The very nature of wind waves requires a large number of small devices for its energy extraction. Waves have the distinction of making more energy available as energy is extracted, due to the inefficiency at which energy is transferred from the wind to the sea at highly developed sea states.
Engineers and designers have been repeatedly discouraged in their attempts to capture wave energy because the occasionally unleashed fury of the sea destroys stations. The force is such that a ton block of concrete has been found inland, after a storm, at about 5 km from shore.
Conversion of energy devices can provide propulsion, buoy power supply, be offshore or shore-based plants. A physics classification would recognize devices that intervene in wave orbits, utilize the pressure field, are accelerative, use horizontal transport from breaking waves.
Some 38 systems have been described that fit into four broad types: surface profile variations of travelling deep water waves, subsurface pressure variations, sub-surface particle motion, and naturally or artificially induced unidirectional motion of fluid particles in a breaking wave.
Their economic feasibility has been repeatedly put in doubt. Generators designed along the lines of conventional aero-generators have been proposed. Waves are commonly available and could be harnessed in far more sites than tides. Numerous large megapolis and conurbations located near the shore would be potential consumers of wave energy, but so would coast sited industries. The systems involve thus either a movable body, an oscillating column or a diaphragm. Researchers usually cite as advantages of harnessing wave energy that they are pollution free, widely available, a low cost operation, that additional units provide easily additional power, their siting on unused shore-land, installations can double as protective devices for harbors and coasts, generators are more efficient than those of fossil fuel conventional plants, are a power source that is complementary to others, their output is unaffected by weather or climate, the size of waves can be fairly well predicted, potential coupling of stations to desalination plants, benign impact on environment and ecology.
Wave energy has been harnessed recently in sophisticated plants particularly in Sweden and Norway. A comprehensive British study yielded many proposals, but the matter has been, for all practical aspects, been laid to rest. Japan has a very active research program, on-going for decades, which led to some large scale efforts, e. Like for tidal power, there are modest devices that can put wave energy to work and which, consequently are more affordable.
In California, close to a hundred years ago, wave power was used to light a wharf underneath which panels had been suspended. At Royan, close to Bordeaux, France, waves provided electricity to a home using an air turbine driven by water oscillation in a vertical borehole. In Atlantic City, New Jersey, floats attached to a pier were activated by horizontal and vertical motion. At Pointe Pescade, Sidi Ferruch a low-head hydro-electric plant supplied electricity from a fore bay with converging channels.
In Sweden an auto-bailer bilge pump has been placed into service, the sea-lens concept has been developed in Norway, and hydraulic pumping over pliable strips in concrete troughs have been proposed by a Boston, USA firm. Though these approaches were either uneconomical or too small at the time, this may not be the case today. Efforts towards the design of economic devices are being made. Whittaker stated that wave power is a potentially viable technology that could make a significant contribution, to not only European, but also the world energy demand.
A somewhat similar son de cloche has been heard in the United States. Indeed, the US Electric Power Institute reports that wave power may be economically viable, but would need a production volume of 10—20 GW. Hawaii, Northern California, Oregon and Massachusetts are proposed as the best sites. It even expressed a preference for waves to wind because of lesser visibility and lower profile in addition to better dispatchability. American researchers concluded that to make such significant contribution sustained research is needed into the application of wave power to the offshore production of hydrogen.
Center 13, 63— Charlier and Justus, , op. In Chung, J. Offshore and Polar Engng Conf. Recent publications on wave power in India include e. Raju, V. The Indian researchers of IIT also developed a power system using the piezo-electric effect: plastic sheets are to be suspended from floating rafts and secured to the ocean bottom.
As waves lift the rafts, the sheets bend and generate electricity in the process. A full-scale pre-production prototype was built in , and field-tested in The number of such machines required to offer a significant saving of traditional fuels, is however rather large, the space required not minimal.
The company views a field of 1 to 2 km2 wherein 40 Pelamis would be installed. The total output of the farm, 30 MW, is potentially sufficient power to fill the needs of 20, homes Fig. The Pelamis device belongs to the group of semi-submerged articulated structures, of which other types have been tested and proposed in the past. Hydraulic arms resist the wave motion which pumps an intermediary fluid through motors by the way of smoothing accumulators.
Yet, some of the objections voiced against wave energy conversion schemes, and occasionally confirmed by experience, remained unanswered and proponents would gain support if addressed.
Nothing would prevent, except perhaps the need for space, this 46 Charlier, R. A wave farm has been placed off the Portugal coast in The Archimedes Wave Swing generator—designed and developed by a Scottish company—completed successful trials in Portguese waters. The system is moored to the seabed and is invisible from the surface.
Electricity is generated as waves move an air-filled upper casing against a lower fixed cylinder. The technology is Dutch in origin. The 2. Wave power has been used, however, for close to a century in Royan, Monaco, a pier had been lit by wave energy in Pacifica, California, a beach had hosted a simple machine, systems had provided mechanical power, etc and pilot plants provided current in Scotland and Norway to mention just two locations.
Generated current is led to the continent via submarine cable. Refining of meteorological equipment and methods currently allows prediction of force and height of waves up to six to seven days in advance. Costs are about the same as that of a wind-system—an approach to alternative energy already endorsed by Portugal earlier—but optimistic prognoses of the designers assert that the wave farm will yield three times that of the wind farm.
The same optimists plan to establish 28 more floating centrals by mid Besides wind and waves, the Portuguese are also eyeing the sun as an alternative source of energy. They started construction, in , of what may well be the largest photovoltaic energy conversion plant, intending to connect no less than hectares of sun-panels. It is not always a matter of producing domestic or industrial electricity. The up and down movement imparted by waves to a ship produces power than considerably 47 Cf.
Some ships likewise have added to their upper-structure panels to absorb marine wind power. In Mexico experiments were conducted on a wave-powered pump system to flush stagnating water in foreshore lagoons. Ireland concentrated on oscillating water column systems. The European Union contributed to the funding of an oscillating water column plant to substitute, on Pico Azores wave power to diesel.
The OWC was deployed on the Island of Islay utilizing a natural rock gully, thus saving on construction outlay and facilitating maintenance access. The University of Edinburgh was the site of S. Belgium examined a decade or so ago, the possibility to use wave power to reduce silting in the harbor of Zeebrugge. It functioned properly but was unfortunately wrecked in during a particularly heavy storm.
It has not been reconstructed thus far The OTEC uses the difference of temperature prevailing between different ocean waters layers to produce electrical power. Statisticians eager to impress the amount of energy available stress that in the waters between the tropics the quantity of heat stored daily by the surface water layers in a square kilometer equals the burning of 2, barrels of oil.
The deep-water group velocity is half the phase velocity. In shallow water , for wavelengths larger than about twenty times the water depth, as found quite often near the coast, the group velocity is equal to the phase velocity.
Among these was the concept of extracting power from the angular motion at the joints of an articulated raft, which was proposed in the s by Masuda.
A number of university researchers re-examined the potential to generate energy from ocean waves, among whom notably were Stephen Salter from the University of Edinburgh , Kjell Budal and Johannes Falnes from Norwegian Institute of Technology now merged into Norwegian University of Science and Technology , Michael E. McCormick from U. Mei from MIT.
Stephen Salter's invention became known as Salter's duck or nodding duck, although it was officially referred to as the Edinburgh Duck. Nevertheless, a few first-generation prototypes were tested at sea. More recently, following the issue of climate change, there is again a growing interest worldwide for renewable energy, including wave energy. EMEC provides a variety of test sites in real sea conditions. Its grid-connected wave test site is situated at Billia Croo, on the western edge of the Orkney mainland, and is subject to the full force of the Atlantic Ocean with seas as high as 19 metres recorded at the site.
Locations are shoreline, nearshore and offshore. Types of power take-off include: hydraulic ram , elastomeric hose pump , pump-to-shore, hydroelectric turbine , air turbine,  and linear electrical generator. When evaluating wave energy as a technology type, it is important to distinguish between the four most common approaches: point absorber buoys, surface attenuators, oscillating water columns, and overtopping devices. Generic wave energy concepts: 1.
Point absorber, 2. The Russians have built a small kW device near Murmansk that was later followed by a Australia is also developing tidal power technologies  Figure 4: Tidal Barrage System  2.
Wave energy can be converted into electricity through conversion of the movement of water surface or changes in water pressure as waves propagate. Figure 2: Tidal Barrage System  Most devices use the undulating motion of the water waves to mechanically power a pump or turbine that Another concept being explored is the tidal fence.
These creates electricity. Other devices use hoses connected to are vertical axis turbines mounted within a fence structure, floats that ride the waves. The rise and fall of the float and operate like a revolving door as shown in figure 2.
It encloses a Comprehensive reviews of the development of technology column of air above a column of water. As waves enter the and resources on ocean current energy devices are given in air column, they cause the water column to rise and fall. This alternately compresses and expands the air column. The circulation of wind above surface water together with As the wave retreats, the air is drawn back through the the uneven heating of the seawaters from the sun creates turbine as a result of the reduced air pressure on the ocean the ocean currents throughout the world.
A number of OWC devices have been installed worldwide, with several of them being built into a breakwater to lower overall construction costs. One recent development is given in ref .
Figure 6: McCabe Wave Pump  Areas that typically experience high marine current flows are in narrow straits, between islands and around headlands.
Entrances to lochs, bays and large harbours often also have high marine current flows. Several studies have been carried out on the energy potential of marine currents, but there have been few on the engineering requirements for utilization of the resource.
Commissioned as the Mighty Whale, the and a small number of prototypes and demonstration units vessel was designed to be anchored to the seabed but can having been tested. Most concepts involves turbines be remotely controlled from shore.
Beyond producing rotating either in the vertical or horizontal axes: electricity, Japanese researchers have found that the calm seas created astern of the Mighty Whale can be used for fish farming or water sports . Horizontal axis turbines axial flow turbine. The tapchan, or tapered channel system, is a wave-energy This is similar in concept to the widespread horizontal axis power generation device that has its roots in traditional wind turbine.
Prototype turbines of up to 10 kW have hydroelectric power plant technology.
The system consists been built and tested using this concept. There are of a tapered channel, which feeds into a reservoir currently plans to install a demonstration machine of constructed on cliffs above sea level. The narrowing of the kW off the south coast of the United Kingdom. This channel causes the waves to increase in height as they concept has also been tested on a small scale in a number move toward the cliff face.
The waves spill over the walls of countries, including Norway. The requirements of low tidal i. Vertical axis turbines cross flow turbine. Recent development in this Both drag and lift turbines have been investigated, area is reported in ref . The best- Other devices such as the McCabe Wave Pump  and known example is the Darrieus turbine with three or four the Pelamis sea snake ,  use the attenuator thin blades of aerofoil cross-section.
Some stand-alone concept. In this case, the differing heights of waves along prototypes have been tested, including a 5 kW Darrieus the length of the device causes flexing where the segments turbine in the Kurushima Straits, Japan. According to ref. Waters off Sarawak show slightly greater depth of up to m.