Marine energy 1

Marine energy

Renewableenergy

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•• v•• t• e [1]

Marine energy or marine power (also sometimes referred to as ocean energy, ocean power, or marine andhydrokinetic energy) refers to the energy carried by ocean waves, tides, salinity, and ocean temperature differences.The movement of water in the world’s oceans creates a vast store of kinetic energy, or energy in motion. This energycan be harnessed to generate electricity to power homes, transport and industries.The term marine energy encompasses both wave power — power from surface waves, and tidal power — obtainedfrom the kinetic energy of large bodies of moving water. Offshore wind power is not a form of marine energy, aswind power is derived from the wind, even if the wind turbines are placed over water.The oceans have a tremendous amount of energy and are close to many if not most concentrated populations. Oceanenergy has the potential of providing a substantial amount of new renewable energy around the world.[2]

Potential of Ocean EnergyThe theoretical potential is equivalent to 4-18 million ToE.

Theoretical global ocean energy resource[3]

Capacity(GW)

Annual gen.(TW·h)

Form

5,000 50,000 Marine current power

20 2,000 Osmotic power

1,000 10,000 Ocean thermal energy

90 800 Tidal energy

1,000—9,000 8,000—80,000 Wave energy

Indonesia as archipelagic country with three quarter of the area is ocean, has 49 GW recognized potential oceanenergy and has 727 GW theoretical potential ocean energy.[4]

Marine energy 2

Forms of ocean energy

RenewableThe oceans represent a vast and largely untapped source of energy in the form of surface waves, fluid flow, salinitygradients, and thermal.Marine and Hydrokinetic (MHK) or marine energy development in U.S. and international waters includes projectsusing the following devices:• Wave energy converters in open coastal areas with significant waves;• Tidal turbines placed in coastal and estuarine areas;• In-stream turbines in fast-moving rivers;• Ocean current turbines in areas of strong marine currents;• Ocean thermal energy converters in deep tropical waters.

Marine current power

Main article: Marine current powerStrong ocean currents are generated from a combination of temperature, wind, salinity, bathymetry, and the rotationof the earth. The sun acts as the primary driving force, causing winds and temperature differences. Because there areonly small fluctuations in current speed and stream location with no changes in direction, ocean currents may besuitable locations for deploying energy extraction devices such as turbines.Ocean currents are instrumental in determining the climate in many regions around the world. While little is knownabout the effects of removing ocean current energy, the impacts of removing current energy on the farfieldenvironment may be a significant environmental concern. The typical turbine issues with blade strike, entanglementof marine organisms, and acoustic effects still exists; however, these may be magnified due to the presence of morediverse populations of marine organisms using ocean currents for migration purposes. Locations can be furtheroffshore and therefore require longer power cables that could affect the marine environment with electromagneticoutput.

Osmotic power

Main article: Salinity GradientAt the of rivers where fresh water mixes with salt water, energy associated with the salinity gradient can beharnessed using pressure-retarded reverse osmosis process and associated conversion technologies. Another systemis based on using freshwater upwelling through a turbine immersed in seawater, and one involving electrochemicalreactions is also in development.Significant research took place from 1975 to 1985 and gave various results regarding the economy of PRO and REDplants. It is important to note that small-scale investigations into salinity power production take place in othercountries like Japan, Israel, and the United States. In Europe the research is concentrated in Norway and theNetherlands, in both places small pilots are tested. Salinity gradient energy is the energy available from thedifference in salt concentration between freshwater with saltwater. This energy source is not easy to understand, as itis not directly occurring in nature in the form of heat, waterfalls, wind, waves, or radiation.[5]

Marine energy 3

Ocean thermal energy

Main article: Ocean thermal energyThe power from temperature differences at varying depths.

Tidal power

Main article: Tidal powerThe energy from moving masses of water — a popular form of hydroelectric power generation. Tidal powergeneration comprises three main forms, namely: tidal stream power, tidal barrage power, and dynamic tidal power.

Wave power

Main article: Wave powerSolar energy from the sun creates temperature differentials that result in wind. The interaction between wind and thesurface of water creates waves, which are larger when there is a greater distance for them to build up. Wave energypotential is greatest between 30° and 60° latitude in both hemispheres on the west coast because of the globaldirection of wind. When evaluating wave energy as a technology type, it is important to distinguish between the fourmost common approaches: point absorber buoys, surface attenuators, oscillating water columns, and overtoppingdevices.The wave energy sector is reaching a significant milestone in the development of the industry, with positive stepstowards commercial viability being taken. The more advanced device developers are now progressing beyond singleunit demonstration devices and are proceeding to array development and multi-megawatt projects.[6] The backing ofmajor utility companies is now manifesting itself through partnerships within the development process, unlockingfurther investment and, in some cases, international co-operation.At a simplified level, wave energy technology can be located near-shore and offshore. Wave energy converters canalso be designed for operation in specific water depth conditions: deep water, intermediate water or shallow water.The fundamental device design will be dependent on the location of the device and the intended resourcecharacteristics.

Non-renewablePetroleum and natural gas beneath the ocean floor are also sometimes considered a form of ocean energy. An oceanengineer directs all phases of discovering, extracting, and delivering offshore petroleum (via oil tankers andpipelines,) a complex and demanding task. Also centrally important is the development of new methods to protectmarine wildlife and coastal regions against the undesirable side effects of offshore oil extraction.

Marine energy developmentThe UK is leading the way in wave and tidal (marine) power generation. The world's first marine energy test facilitywas established in 2003 to kick start the development of the marine energy industry in the UK. Based in Orkney,Scotland, the European Marine Energy Centre (EMEC) [7] has supported the deployment of more wave and tidalenergy devices than at any other single site in the world. The Centre was established with around £36 million offunding from the Scottish Government, Highlands and Islands Enterprise, the Carbon Trust, UK Government,Scottish Enterprise, the European Union and Orkney Islands Council, and is the only accredited wave and tidal testcentre for marine renewable energy in the world, suitable for testing a number of full-scale devices simultaneously insome of the harshest weather conditions while producing electricity to the national grid.Clients currently testing at the centre include Aquamarine Power, Pelamis Wave Power, ScottishPower Renewablesand Wello on the wave site, and Alstom (formerly Tidal Generation Ltd), ANDRITZ HYDRO Hammerfest, OpenHydro, Scotrenewables Tidal Power, and Voith on the tidal site.

Marine energy 4

Beyond device testing, EMEC also provides a wide range of consultancy and research services, and is workingclosely with Marine Scotland to streamline the consenting process for marine energy developers. EMEC is at theforefront in the development of international standards for marine energy, and is forging alliances with othercountries, exporting its knowledge around the world to stimulate the development of a global marine renewablesindustry.[8]

Environmental effectsCommon environmental concerns associated with marine energy developments include:• The risk of marine mammals and fish being struck by tidal turbine blades;• The effects of EMF and underwater noise emitted from operating marine energy devices;• The physical presence of marine energy projects and their potential to alter the behavior of marine mammals, fish,

and seabirds with attraction or avoidance;• The potential effect on nearfield and farfield marine environment and processes such as sediment transport and

water quality.The Tethys database seeks to gather, organize and make available information on potential environmental effects ofoffshore wind energy development.

References[1] http:/ / en. wikipedia. org/ w/ index. php?title=Template:Renewable_energy_sources& action=edit[2] Carbon Trust, Future Marine Energy. Results of the Marine Energy Challenge: Cost competitiveness and growth of wave and tidal stream

energy, January 2006[3][3] International Energy Agency, Implementing Agreement on Ocean Energy Systems (IEA-OES), Annual Report 2007[4] Indonesian Ocean Energy (http:/ / jakarta. indopos. co. id/ ?p=4742)[5] http:/ / www. oceanenergy-europe. eu/ index. php/ policies/ technologies/ 13-technology/ 46-salinity-gradient[6] http:/ / www. oceanenergy-europe. eu/[7] http:/ / www. emec. org. uk/[8] http:/ / www. emec. org. uk/

External links• The Ocean Energy Systems Implementing Agreement (http:/ / www. ocean-energy-systems. org)• European Ocean Energy Association (http:/ / www. eu-oea. com)• The European Marine Energy Centre (EMEC) (http:/ / www. emec. org. uk/ )• Ocean Energy Council (http:/ / www. oceanenergycouncil. com)• SuperGen UK Centre for Marine Energy Research (http:/ / www. supergen-marine. org. uk)• Marine Energy Times, information website (http:/ / www. marineenergytimes. com)• Tethys - Environmental Effects of Renewable Energy from the Sea (http:/ / tethys. pnnl. gov)

Article Sources and Contributors 5

Article Sources and ContributorsMarine energy  Source: http://en.wikipedia.org/w/index.php?oldid=620075003  Contributors: Alpha 4615, Andy Dingley, Barrodrajesh, Brewmastermk, Chris55, Correctionwriter,Dawnseeker2000, DirkvdM, Elcquid, Epipelagic, Eszwaqeszwaq, Gsarwa, Iridescent, Ita140188, Jessicaowen, Joeinwiki, Jonathan Oldenbuck, Lisamack86, Manning Bartlett, Masters Marketer,Mathew Topper, MrOllie, Nimur, NuclearEnergy, Ocharpen, Peterkingiron, Rehman, Rich Farmbrough, Rob OEE, Rsrikanth05, Shinkansen Fan, Sonicyouth86, Tehanim, Tokyogirl79,Vegaswikian, WadeSimMiser, Wavelength, Widr, 33 anonymous edits

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