Ocean Energy: The Future of Renewable Energy Generation

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Ocean Energy: The Future of Renewable Energy Generation Muhammad Anas Siddiqui1, Syed Muhammad Ahmed Latifi2, Muhammad Atif Munir3, Syed Mohsin HussainKazmi4and Jugraj Singh Randhawa5 1, 2,4 3,5 1

Department of Electrical Engineering, University of Windsor, Windsor, Canada

Department of Mechanical Engineering, University of Windsor, Windsor Canada

[email protected], [email protected], [email protected] [email protected] 5

[email protected]



Abstract— As the threat of global climate change caused by emission of green house gases in our atmosphere and utilization of fossil fuel deposits are decreasing fast, and are growing concern to the future of electric power generation. Our study is conducted to discuss about the generation of electricity utilizing ocean energy (tides and waves). Energy extracted from ocean is considered as a renewable source of energy and it is the future power plant of our planet as ocean covers 70% of the surface of Earth. Countless research and development is undergoing and huge investments in ocean energy projects are taking place worldwide. Our study presents a brief review about the background of tidal power. It also highlights the uses, advantages and design aspects of the marine current turbine being used in Bay of Fundy Canada. Furthermore, we have discussed the conversion of tidal energy into electricity and shade light on two rotor turbine. Index Terms— Electric power, Ocean energy, Tidal power, Tidal turbine, Renewable energy and Wave energy.

I. INTRODUCTION

Growing energy crisis, decrease in deposits of nature resources and the climate change caused by emission of green house gases is leading to the development of new technologies for sustainable power generation is gaining importance. Many organizations have stepped forward and invested millions of dollars in research, development and production of alternative energy sources. Among many others, tidal and wave energy source is providing infinite supply of clean energy. The power of the ocean and turbine advanced technology guarantee much more predictable energy output than other renewable energy like solar and wind. Around 70% of our planet Earth surface is covered with the ocean and thus it produces an immeasurable amount of energy in the form of tides and waves. Ocean energy is currently in its developing stage and will soon come into the lime light in the energy industry. Our research paper examines the basics behind wave and tidal energy and we will give brief review about few technologies for harvesting energy. Since new technologies are rising, there is a great diversity among devices that can be available in future to generate electricity from either waves or tides. As the industry is developing, there would be a wide variety of selections available, based on their generation level, cost, and durability. However, it‟s expected that a single device will succeed; the best

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possible device will mostly be reliant on the atmosphere in which it will be utilized. Solar and wind energy are unpredictable whereas wave and tidal energy is predictable but there is a problem with its continuity when using wave and tidal energy. Problem occurs for those societies which are only relying on these sources. It will also be difficult in integrating it to the electrical grid. In order to analyze the wave and tidal devices following sites are acting as testing sites like the Bay of Fundy is located in the Nova Scotia province.

Fig. 2, Tidal Amplitude in Mina Basin [26]

II. HISTORICAL BACKGROUND

Fig. 1, Bay of Fundy Tidal Potential Map [25]

The SeaGen 1.2MW commercial demonstrator has been build up on the basis of results obtained from sea flow, the world‟s first full-scale tidal turbine (300KW) installed by Marine Current Turbines of Lyn mouth Devon U.K in 2003. An accord has been made with Canada's Maritime Tidal Energy Corporation in 2007 to develop tidal resources in the Bay of Fundy with a tidal range exceeding 15 metres (49 ft), and flows of up to 14 kilometres per hour (8.7 mph), this area has long been preferred as the most potential source of tidal power and the implementation of innovative tidal flow concepts indicate the coupled distribution and environmental problems of barrage schemes are no longer effective.

Tidal energy was firstly used as tide mills on the seashores of Spain, France and Britain in 800 A.D. It is one of the oldest compositions of energy used by humans but it is unlikely lost its antecedent in the enigma of history. Tide Mills was a storage pond filled by the incoming (flood) tide through a lock and rinses the outgoing (low tide) through a water wheel. The tide turned water wheels, producing mechanical power to mill grain and energy was obtainable for approximately 2-3 hours generally two times a day. The demand for energy makes way for the early tidal barrages to develop on an insignificant output until 1960; the first major breakthrough in modern era of tidal power plant was built, near St. Malo, France. The hydro mechanical devices that impeller and the exceed waterwheel have paved the way for high-efficiency fluorescent lamps type hydro power turbine or generator sets. The tidal barrage in St. Malo utilizes a 240MW low-head fluorescent lamps type turbine generator set which became operational in 1965. Since then, the barrage is operational without missing a single tide or wave from more than 37 years. Since then, there were an increasing number of commercially viable tidal barrage situated in service in France and afterwards Canada, Switzerland, United Kingdom, China and so on. A. Technology

There are various techniques available in order to extract energy from tides and waves. Ocean energy is moderately becoming a latest trend in energy

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industry as there is a diverse range of model devices available but a small amount of them are in actual mounted and generating electricity. Additionally, several numbers of devices are designed particularly for a certain site or meant for precise tidal and wave conditions. Whereas, it would probably be few devices that will in reality are marketable, it looks like that tidal and wave technology will need to be particularly designed to adjust in the ocean circumstances of a given site for a long life span. B. OTEC

OTEC is a structure which frequently utilizes the radiance dilemma deposit away commencing the stifling water. The planet's marine heaps occupation as being a enormous power of tenderness fundamentals. The use of facilities that must be as a part of temperature involving hot surface area oceanic mineral water as well as cool distant ocean to make power [12]. Humid basics modification being a necessity expansion those progressions over sun controlled. The composition utilizes sea normal humid persuade the way that this ocean's tiers of water get clearly identifiable temperature. That is hammering an electrical making cycle. An OTEC system can craft a substantial measure of energy [6].

Fig. 3, Fundamental OTEC System [24]

The marine is in this behavior is an immeasurable renewable resource, this create an opportunity for sky-scraping sum of electrical energy almost in billions. This is credible to spot regarding a thousand watts of simple load, as specified by a few professionals. The sub-zero, insightful ocean utilized as a part of the OTEC attitude is also wealthy in appendage, and it can be exploited to benefit both marine creatures and vegetation nearby the shore. OTEC create reliable, base-load power new water, and freshen choice [4-6].

It necessitates a tenderness density of around 360F or 260C. The modification subsists involving the surface temperature and seawater considerable year all in the course of the humid regions throughout the world. For power, either use a working flowing with a stumpy perimeter e.g., salts or warm water sea plane or transformed into condensation warming up with balmy sea water in other words soluble base or water tepid sea decreasing the pressure. The immensity of magnification steam rotates a turbine and generates energy [5]. Region near shore are a generously proportioned number of very useful asset then rest of the areas.. OTEC plants mounted to the major terrain frame at up to 100 M, no matter what bracket mounted administrative centre least eye-catching and surplus exaggerated than land collaborators could lead to the peripatetic OTEC administrative centre with a considerable force boundary [3]. C. Wave Energy

Waves are formed due to exchange of power from wind to the water. The winds are formed due to sun. The land and water operate as cosmological discharge hoarders; deep sea water is the result of resourceful of these. When the water is hot it is heated and it turns into a form of steam which further turns into air above it. The hot air then ascends; displace cold air, which fall down to be heated by the water in turn. Resulting, air currents are produced. As these currents propel on the surface of the water, roughness between them causes the water to extend, the result of which is miniature currents. This affects the surface to contact between the water and wind to extend, and gradually larger waves. In addition, waves can also be generated by huge disturbances, which result in tsunamis. Despite the fact that they are uncommon, it is still significant while shaping utmost load energy tool must survive. It is approximated entire power of waves broke on the seashore is approximately 2-3 Terawatts. Best possible locations for wave energy having density typically 65 MW solitary mile of seashore, or 70 kW of power for every meter of wave peak length [7]. In winters this number raise upto 170 kW/m and can attain as high as 1 MW/m during storms [8]. In winter waves possess more energy than in other seasons. It is essential to notice that once

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wave is produced it could voyage greater distances without any loss in energy. This provides waves a total of certainty: yet in phase of modest wind and hence miniature wave produced. Waves generated from distant areas can still be added to energy generation. D. Tidal Energy

Tidal power makes use of the energy from the movement of the tides to generate electricity. Tides are first and foremost drive by the natural gravity drag of moon. According to statistics every coastline region gets two elevated and two small tides and two tiny tides over 24 hours. Tidal energy is completely knowable, creating it a lot simple to fit into the framework. The dissimilarity between tides must be at most 5 meter > 16 ft thus; this technique is used to control tidal power effectively. Fortunately there are only 40 places on our planet Earth that posse‟s tidal behavior [10]. At this time we need cost efficient power generation from tidal stream turbines that indicate high speed superior than 2.25 m/s, in a deepness of water between 20 to 30 m [11]. These limitations also to a great extent maximize the possibility of extracting tidal energy in a large amount. On the other hand, as technology enhances these limitations became less rigid.

Fig. 4, Vertical Rotor Tidal Turbines [22]

E. Oscillating Water Columns [9]

Oscillating water columns produce electrical energy as the waves strike the cylindrical tube. Because of the waves, water in the column rise and fall, after that it propels air doing pendulum motion at the upper portion at beam where there is an air-steering turbine. The motors are then triggered to be in motion resulting in the production of electricity [9].

Fig. 5, The Survivor Limpet [23]

The Limpet, shown in Fig.5, is situated on the Isle of Islay and is the first of its kind a commercial workable wave originator in the world. Constructed by the Scottish company Wavegen, it is a move back and forth water pillar. The waves generated is a pillar look alike of water within the machine that produce a pressure in the air compartment above the column, causing two parallel rotating motors to spin. Each are simultaneous to produce an amount up to 250 kW, for a total of 500 kW [9]. The Limpet was developed to endure the nastiest ocean environment. Assembled with a high solidity of toughen fortification than a nuclear trench, the Limpet continue to exist the nastiest blizzard on Islay in living remembrance. The severe marine oodles predictions are perhaps greatly superior to any authentic oodles the Limpet determination. For this reason feasible foremost cost cutback in the upcoming prototype technology could be a enhanced approximation of authentic marine environment presented [9]. F. Wave Surge Device [13]

An additional type of wave energy device is the wave surge. They are installed on the coast; it store the waves and conduit it into a lofty reservoir. Thus using conventional hydro power machinery, the water sets free through the basin, rotating the rotors. These machinery cause trouble when constructing

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due to the locality of the sea cliff, where the waves are the strongest. These frequently need blowing some part of the cliff to make space for the basin, which is a costly venture. Also, accessibility, installation and maintenances of these devices are increasingly costly.

figure below has been used since 1966, produces an average of 240 megawatts power. This produces approximately 90 percent of the electric power, which is used in Brittany. is an experimental station of tidal power is the Annapolis Royal station which produces around 20 megawatts of energy from the Bay of Fundy and is situated in Nova Scotia [13].

Fig. 6, Block Diagram of Wave Surge Device [27] III. CONVENTIONAL METHOD

Generation of tidal energy has same method as it is in the hydroelectric power plants. The doors and the turbines installed along a barrage or dam, extends through the tidal basin‟s opening, such as an estuary or a dam. A diverse level of fluid is produced on the sides of the barrage by the tides. The doors are opened as this difference gets increased, causing the water to flow out. This water thus strikes with turbine blades and causes them to rotate, and electric power is generated. Table. 1 summarizes all the plants of tidal power, which have been designed. Table. 1 Tidal Energy Sites [1]

Fig. 7, La Rance Station [2]

Because of the inadequate number of locations that possess a lesser amount of series for tidal stream systems, attentions have been transferred from established tidewater barrage systems to the capture of coastal stream current. Some of the technologies, undergoing development are tidal fences and turbines. IV. TIDAL ENCLOSURE

The tidal enclosures are the fences of the cycle of revolving doors, turned through typical coastal water contemporary. A tidal fence has been designed by Blue Energy Canada that makes use of a vertical moving turbine, as shown in Fig.8, below.

Station La Rance, integrated in a barrage through the tidewater of the Rance River, France, is the one in the world with commercialized tidal power generation station. This station, shown in the

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Fig. 8, Series Tidal Fence of Blue Energy Inc. Canada [28]

Its design has many advantages: 1) The components of the generator components can be accessed by top of the sea surface, which reduces the cost of repairs; 2) The structure is built in such way that allows the life under sea to move. 3) The upper part of the tidal fence can be used for transport. V. TIDAL MARINE TURBINES

The turbines are much as immersed windmills. Perfectly mounted in the ocean, at the place that has higher level of currents; the large volume of stream which flows the blades of turbines, produces electricity. On the contrary to wind turbines, this attains the great gain of the expectedness: merely the tides distant unfailing as compared to wind, the pattern of the tides can also be predicted in advance. Figure 3 below shows a tidal turbine having a capability of 300 kilowatt, designed by Marine Current turbines (TCM) installed in the Bristol Channel in 2003.

Fig. 9, Tidal Turbine at Bristol, United Kingdom [29]

The most recent proposal by the MCT for tidal turbines consist of two single beds inner stream rotors, approximately fifteen meters to twenty meters in width. The rotors push a generator through gearbox. Two power supply units are mounted to both sides of the center steel beam. This centre steel beam has a diameter of approximately 3 m and for the purpose of supporting the turbine it is immersed into the seabed [11]. Tidal turbines have a great many advantages over the wind turbines. The wind turbines have a section of sheet up to 300 feet, to the difference of fifteen to thirty feet in diameter desired for an oceanic device of production potential equal as wind turbine. Moreover, the tidal turbines rotate around 30 revolutions in one minute, approximately the half of the wind turbines speed. Such smaller magnitudes are only possible because of higher water density i.e ten times the density of air, and that‟s how it has a greater energy density. In addition to this, the Tidal Turbines can be of steel instead of expensive and light in weight materials that are used to construct wind turbines. Moreover, the turbines are supplied by a source that predictable as compared to the wind turbines [12]. VI. FEASIBILITY

As we have many ideas to exploit the energy from ocean waves and tides, still feasibility is an issue. The turbine should generate a great amount of energy to be able to be reasonable in energy generation sector. Though, an enormous total of energy is present in the motion of tides and waves in

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oceans of the world, relatively few places with the required amount ocean energy is present to justify energy devices installation. Another great hindrance in the way of the production of energy from oceans is within itself. The suitable locations for the installation of energy turbines that waters can be more harsh currents. Many new technologies have been torn when they are practically placed at sea. Accordingly, ocean energy turbines should be strong enough to bear the worst conditions. This is achieved through detailed studies to verify compulsory sustainability that is significant investments in structures and materials that can bear these loads. Fig.,10, below shows a map of the world with average energy of waves along the coastal areas all over the world. It is obvious in this card that there are relatively few places in the world for the placement of energy systems with the current technologies. In the present state of technology, the waves are possible as the source of energy only for some parts of the world, like Europe, some of the parts of Australia, and the South of South America and North of North America.

Fig. 10, Average Energy Waves Carrying along Coastline (kW per meter, per wave) [30]

In United States of America merely five states have good tidal flow and eight states with sufficiently physically powerful waves to rotate turbines [14]. With so little opportunities in the United States at the national level, it does seem likely that the Congress would support projects of oceanic energy from these states. Only one company has received funds from the federal government for the deployment of the ocean energy: $12 million has been given to the navy of U.S. for pilot buoy projects, offshore of Hawaii. However, small projects of oceanic energy have already been started in Rhode Island, Massachusetts, New York, Washington, Hawaii, and California. A panel of

Supervising personnel‟s was called for the production of 150 kilowatts of tidal energy in January, the year 2006, in San Francisco [14]. European Union (EU) the officials believed that in the year 2010, sources of oceanic energy will produce over nine hundred and 50MWatts. This was sufficient to feed a million households in the world. Between the Scarba and Jura islands, is situated the Argyll‟s whirlpool that may generate up to 2GWatts of electric power, if the tidal or oceanic power devices are introduced, but such resources are very rare so specially designed devices should be used for maximum energy production [15]. VII. ECONOMICAL ASPECTS

The cost of the devices for tidal energy production relies greatly on these aspects: 1) Amount and consistency of reserve. 2) Maintenance as well as fabrication for converting tidal into electrical energy. 3) Transmission of power as of production location to public. Noticeably a number of regions of the world do not have enough ocean energy for cost-effective tidal energy equipments. While the tides are very predictable, reliance on the energy extracted by wave triggered equipments can be tragic especially in cases of complete calm and quite ocean. However, this issue can also arise in other energy resources such as solar and wind energy. In addition, it is much more an undesirable event that, the calm oceans may observe as compared to the winds on a cloudy day. However, the option is available and the investment in standby classification could be essential. The capital expenditure is the most important factor to produce the energy of waves. It is a noticeable difference of technologies of fossil fuels, where the fuel is the main reason for the cost. However, because of the research and the modification of existing models it is now economical as compared to past models. The expenditure in their majority is going to build the device, its installation, and its connection to the electrical network, the device must be durable, flexible and resistant to weathering. In addition, there are costs associated with a location of the plant. For devices, like the

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tidal turbines, a solid foundation is required which is not easy to achieve in the ocean‟s sandy. Also, there is a requirement of maintenance because seawater is corrosive in nature: rust extends on the surface of the device; the force of waves. Maintenance includes eliminating any marine life which may get deposited on the devices and restrict the production of sea luminary. However, the machinery up to date well-built and long-term structures of marine. One must take into account the ships, vessels, docks and oilrigs that have been in use for several years and only requires a minimum maintenance to sustain the utility. In the case of oil extraction locations, in particular, its likelihood to facilitate companies in the energy sector who have supervised the maintenance and construction could broaden their knowledge to this reusable reserve. The expenses inherited in energy broadcast to the society. Shoaling/dispersion process decrease the power per waves peak length as they move closer to the coast. Energy devices of waves are perfectly located to oceanic lowest point of at smallest amount of fifty meters; more close to the shore, waves will drop percentage of energy as a result of friction with the bottom of the sea. Consequently, more energy could be generated in the deep waters as compared to the coast, but then, it is a must situation to analyze an economic technique to transmit it to consumers. Expenditure equilibrium must be comparing the additional expenses for the transmission of electricity from generation devices far more away vs. to the increase in available energy. To be cost-effective, the cost of installation as well as construction should be reduced. Durable device is capable of withstanding the worst possible conditions produced by the oceans, but it is highly expensive and is economically not a good choice. On the other hand, if too many things are cut in the construction of the device for the purpose of cost reduction, the device may not sustain harsh conditions of the oceans then. So we must discover stability between the satisfactory jeopardy which is higher than the normal blizzard may result in breakage to the device as compared to increase of costs to ensure that the device is tough enough to sustain a storm. One of the strategy to solve the problem of harsh ocean conditions is to sink the

device deliberately when the ocean conditions are not harsh and taking it out of water during the storm. But this is suitable for the devices without association, example buoys. But for larger; devices that are secured, must be constructed to withstand the ocean in its best level. Creation of joint ventures between the tidal plants and the devices offshore would be cost effective. For example, it might be feasible to fit the turbines under wind farms that are offshore. As the most windy areas usually have the more large waves, so this will ensure the optimum conditions for working of the two technologies. Other strategy is to use the tides fences as bridges. Japan Marine Science and Technology Center‟s (JAMSTEC) mighty whales are an example of ocean technology. It is a flotation, 50m in length, 1000-tonnes wave platform which produces an average of 110 kW. Taking into account the expenses associated with the construction of the Might Whale, which manufacture oomph at a rate of about 28 ¢/kWh) [13]. For isolated communities and coastal installations, this is now able to offer competitive prices and energy. A claim from Energetech Australia is that the device they possess that is a device with an oscillating column of water will charge about 10 ¢/kilowatt-hour, which might be capable of competition in certain regions which are distant from the electricity network. In the last two decades, technological advancements have brought down the calculated cost of the wave energy in an order of magnitude [16]. The manufacturing costs are reduced with the production and fabrication of more and more ocean devices. In addition, multiple devices including tidal turbines can be fabricated at a single site, such as wind parks. Then, the marginal cost of maintenance and adding more devices would be reduced as soon as the site is developed. With all these improvements, nevertheless, it is probable that the devices of the ocean energy are competitive economically in areas located farther from the electrical network [16]. VIII. SIGNIFICANCE

Ocean as a source of reusable energy can lead to the benefit of reduction in the usage of natural deposits by the world. It is a healthy source of

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generating power because it is pollution free, just the cost of installation and its yearly maintenance. Although the benefits we are getting from ocean energy we should also keep an eye on it environmental and biological impacts of ocean energy extracting device, which should be take into account. IX. NUMBER OF EMISSION OF SOLIDS OR LIQUIDS

Below is the Table 2 that highlights the amount of release of gasses or liquids from a wave energy generating device (turbine). Table. 2 Emissions Expected From Wave Energy Devices [17]

These numbers are expected that vary in function of the different types of machinery and the number of machinery will not generate the emission further than mentioned limits during their production. Today, the majority of the premeditated devices use water hydraulic system so as to eradicate the chance of inherent grease spillages in standard hydraulic systems. Observed, such machinery offer a supply of power that is clean as that of any other technologies of fossil fuels, and infect from certain renewable energy resources. X. ENVIRONMENTAL EFFECTS

Another major concern is affect of wave and tidal energy generation machinery on the natural life of creatures living in the ocean. Even so, the total outcome due to variation in tides and wave patterns on an ecosystem is not known; it is preferred to maintain as the way it is till the equipments are mounted. The La Rance barrage has changed the tides local pattern to some extent and the effects on the environment had been almost vanished. But, this may not be the case possibly for every such facility. From the time when the marine water enter into

delta then it is separated by a barrage, the delta‟s brininess would get reduced. In addition, tides and to the inside of the basin are reduced to half. Thus, the water quality, the movements of sediments, and sediments‟ composition gets altered. This in turn might affect marine life that may result in change habitats of animals. For example, In Canada, for a barrage type tidal power plant, the Bay of Fundy is a promising location. However, it is predicted that a plant of this type can reduce the local tides with a maximum of 15 centimeters. In addition, it is concerned to facilitate the effect of alteration of brininess in the bay can set in motion the "red tide" organisms, which may lead to a paralysis in shellfish [18]. Also, this type of barrage would disrupt the wonks of thousands of species of birds that migrate across the bay. It is specifically a problem with this particular site, but dams and barrages of this extent can cause much other unexpected harm. Also, there are theories that during high tides, this type of tidal barrages can serve as a protection against flooding of coastal areas. And thus, they act as a barrier to storm. Notwithstanding, this potential benefit, the attention has been focused on small waves and tidal devices with a predictability that it will have much less effect on the environment. The effects on the environment depend largely over the environment on locations, and investigations compulsory to keep an eye on each site separately are intimidating. By implementing devices with less significant scale, we could steer clear of loads of the ecological issues. XI. AFFECTS ON WILD LIFE

Curiously, it looks as if to have marine life stimulated largely by these waves and tidal devices. These devices floating in water, may offer refuge to birds and fish as they would prevent fishers and their boats to enter in their surrounding region, thereby, becoming a shelter for nature and might result in increase in birds and fishes population. Presently, there is in reality a strong desire for artificial reef structures for marine life stimulation. In 2000, state of New Jersey has bought more than fifty the subway cars to sag in the waters to stimulate the fish stocks [18]. In addition, these

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configuration merely provide a man made shoal environment, also circumvent by great number of fishing vessels, networks and fishing equipments could be jammed or damaged by these machinery. If it is a convenient demand in favor of asea constructions then appears valid to have the structure, an electric power generation capability. However, tidal enclosures and the tidal barrages can prevent marine life to relocate. The tidal turbine is more wave energy devices and is least harmful to the environment because it does not block migration routes. For all of these technologies, it is important to choose the site that has a minimal impact on the environment. Another disadvantage of these devices including the tidal turbines is the rotation of their blades. However, the average rotation of the blades is about 10-20 rotations per minute. In contrast to this, a propeller of a ship normally runs at faster rate than these oceanic devices. In addition, the tidal turbine is immobile, while the ships are capable of moving swiftly than the marine creatures are capable of moving in the sea. In this case, the devices for tidal energy production of the ocean offer less risk for the organisms in water as compared to the magnitude of effect of ships that are traversing in the seas already. XII. SHIP TRAFFICKING

Energy devices of the ocean can be an obstacle for maritime traffic and can become a trouble if deployed in such quantities that restrict/hurdle marine traffic. This could be particularly hard for the fishing boats, and they will be supposed to avoid the regions with installed wave or tidal energy extracting machinery. It can also become a problem for regions with important tourism and amusement sites. This can rise development in marine energy equipments and are given modern tools of navigation, such as warning devices like the radars. XIII. IMPACTS ON VIEW OF COASTLINE

One of the key concerns of all tidal and waves energy devices are their aesthetics. In general, any obstruction to the view is met with the main opposition of the inhabitants, particularly in view of the sea. This is not only valid for devices of ocean, but also for wind energy. Nevertheless, from the

seashore, many devices are not easily visible; they sometimes appear just above the sea-level and are submerged by the waves, most often. These devices are particularly low profile when one compares with oil platforms or wind farms at sea. On the other hand, Coastal devices can easily be seen from the side but In this case, visual impact is required in order to balance the merit of having an efficient and clear energy source. XIV. CONCLUSION

The wave and tidal energy has been recognized in niche of markets economy, especially in locations that are distant from the grid or in seaward facilities. Because of the developed tools improvement, the established foundation of power extracting equipments is becoming expensive and doubtful in terms of environment sustainability, and the history of success is established with already mounted ocean energy equipment can turn out to be an appealing resource operates more commonly. In fact, the people have got to learn how the ocean energy power can be controlled. The ocean is a very destructive medium especially when it comes to the residing of any ocean device but the vast experience of ship constructions, the wharves and the oceanbased structure, for centuries, has given to the mankind the knowledge necessary to build strong and sustainable energy devices of the ocean. However, as many other sources of renewable energy, ocean energy probably is competitive with fossil fuels, economically but except for the case of communities which are isolated and which are distant from the grid. Even to the extent or the technologies commercially viable and developed, by using energy from the oceans, is limited to sites that have a significant quantity of tides or activity of waves. REFERENCES [1] A. M. Gorlov, “Tidal Energy”, Northeastern University, Boston Massachusetts,USA, pp.2955-2960. http://www.gcktechnology.com/GCK/images/ms0032%20final.pdf [2] Barrage La Rance, http://whereongoogleearth.net/2010/06/18/contest142-answer-barrage-de-la-rance-france/, last accessed February 23rd, 2015. [3] Karen Finney, “Ocean Thermal Energy Conversion”. Guelph Engineering Journal, 1 (2008)17-23. Web. 20 Oct, 2010. [4] Avery, W. C. 1994. „‟ Renewable Energy from the Ocean: A Guide to OTEC „‟. New York: Oxford University Press. [5] Nihous, G.C Syed, M.A and Vega, L.A (1989) ‟‟Conceptual design of an open-cycle OTEC plant for the production of electricity and fresh water „‟.Proceedings International Conference on Ocean Energy Recovery.

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