Tidal Energy

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Tidal power, also called tidal energy, is a form of hydro power that converts the energy of tides into useful forms of power, mainly electricity.

Text of Tidal Energy

  • 1. Explained ByKavan Oza (IU1241060031)Maharshi Pandya(IU1241060034)Ashir Sheth(IU1241060053)

2. Outlines How Tides Occurs? Introduction of Tidal Energy How to Generate Tidal Energy Types of Tidal Power Plant Tidal Scenario In India Advantages Dis advantages 3. Tidal power, also called tidal energy, is a formof hydropower that converts the energy of tides intouseful forms of power, mainly electricity. 4. Tidal forces are periodic variations in gravitationalattraction exerted by moon. These forces create corresponding motions orcurrents in the world's oceans. Due to the strong attraction to the oceans, a bulge inthe water level is created, causing a temporaryincrease in sea level. When the sea level is raised, water from the middleof the ocean is forced to move toward the shorelines,creating a tide. This occurrence takes place in an unfailing manner,due to the consistent pattern of the moons orbitaround the earth. 5. How To Generate Tidal Energy?? Tidal stream generators (or TSGs)make use of the kinetic energy ofmoving water to power turbines,in a similar way to wind turbinesthat use wind to power turbines. Some tidal generators can bebuilt into the structures ofexisting bridges, involving virtuallyno aesthetic problems. Land constrictions such as straitsor inlets can create high velocities atspecific sites, which can be capturedwith the use of turbines. 6. This form of generation has manyadvantages over its other tidalenergy rivals. The turbines are submerged inthe water and are therefore outof sight. They dont pose a problem fornavigation and shipping andrequire the use of much lessmaterial in construction.They function bestin areas where the water velocityis 2 - 2.5 m/s 7. Tidal barrages make use of thepotential energy in the difference inheight between high and low tides.When using tidal barrages to generatepower, the potential energy from ais seized through strategic placementof specialized dams.When the sea level rises and the tide beginsto come in, the temporary increase in tidalpower is channeled into a large basin behindthe dam, holding a large amount of potentialenergy.With the receding tide, this energy is then converted into mechanicalenergy as the water is released through large turbines that createelectrical power through the use of generators. 8. The power available from the turbineat any particular instant is given by:Where,Cd = Discharge CoefficientA = Cross sectional area (m2)G = gravity = 9.81r = density (kg/m3) The discharge coefficient accounts forthe restrictive effect of the flow passagewithin the barrage on the passing water. The equation above illustrates howimportant the difference between thewater levels of the sea and the basin, (Z1-Z2),is when calculating the power produced. 9. Tidal range may vary over a wide range (4.5-12.4 m) from site to site. Atidal range of at least 7 m is required for economical operation and forsufficient head of water for the turbines. A major drawback of tidal power stations is that they can only generatewhen the tide is flowing in or out - in other words, only for 10 hours eachday. However, tides are totally predictable, so we can plan to have otherpower stations generating at those times when the tidal station is out ofaction. 10. This is a 240 megawatt(1 megawatt = 1 MW = 1 million watts)at the mouth of the La Rance riverestuary on the northern coast ofFrance (a large coal or nuclear powerplant generates about 1,000 MWof electricity). The La Rance generating station hasbeen in operation since 1966 and hasbeen a very reliable source ofelectricity for France.It is the only one in Europe but thereIs a possibility that 10% of UKsElectricity demand can be satisfied byTidal energy.. 11. The technology required for tidal power is well developed, and the mainbarrier to increased use of the tides is that of construction costs. There is a high capital cost for a tidal energy project, with possibly a 10-year construction period. Therefore, the electricity cost is very sensitive to the discount rate. The major factors in determining the cost effectiveness of a tidal powersite are the size (length and height) of the barrage required, and thedifference in height between high and low tide. These factors can be expressed in what is called a sites Gibrat ratio.The Gibrat ratio is the ratio of the length of the barrage in metres tothe annual energy production in kilowatt hours (1 kilowatt hour = 1 KWH =1000 watts used for 1 hour). The smaller the Gibrat site ratio, the more desireable the site. 12. Indian Tidal Energy Scenario Tidal Energy is one of the new and emergingtechnologies, which is commercially not viable andstill in Research & Development (R&D) stage. Indiahas a long coastline with the estuaries and gulfs wheretides are strong enough to move turbines for electricalpower generation. 13. Tidal Energy Potential As per the studies, the Gulf of Kutch and Gulf of Cambay in Gujarat andSunderbans area in West Bengal are the only potential sites in India for thedevelopment of Tidal Energy Projects. Central Electricity Authority (CEA) undertook a study for the assessment oftidal energy potential in India. According to the study, the identifiedeconomic power potential is of the order of 8000 MW 14. Region State Tidal Potential (MW)Gulf of Cambay(Khambhat)Gujarat 7000Gulf of Kutch Gujarat 1200Gangatic Delta,SunderbansWest Benga 100 15. In February 2008, under the Tidal Energy Programme, the Ministryof New & Renewable Energy (MNRE) sanctioned a demonstrationproject for setting up a 3.75 MW tidal power plant at DurgaduaniCreek in Sunderbans, West Bengal. The NHPC Limited was given responsibility to execute the project.The total estimated project cost was INR 48 crores, out of which90% (INR 43.20 crores) was to be shared by the MNRE and theremaining 10% (INR 4.80 crores) by the Government of WestBengal. However, the project has been discontinued due to very high tendercost amounting to INR 238 crores against originally estimated costof INR 48 crores. 16. Tidal Power Projects in Gulf of Kutch, A committee was constituted under the CentralElectricity Authority (CEA) on the 900 MW KutchTidal Power Project for estimating the cost of theproject. A techno-economic feasibility study wascarried out by the CEA in 1988 for a 900 MW TidalPower Project. A revised estimate of INR 6184 croreswas worked out for the execution of this project in1993. 17. Mandavi Tidal Power Project (250 MW) inKutch In January 2011, Government of Gujarat signed aMemorandum of Understanding (MoU) for establishing a250 MW tidal power project in Gulf of Kutch with GujaratPower Corporation Ltd. (GPCL) Vadodara, AtlantisResource Corporation, United Kingdom and PerfectMining Energy Solutions (PMES), Singapore. A Special Purpose Vehicle was incorporated in May, 2011and GPCL has taken up a 50 MW tidal power project atMandavi in district Kutch in the first phase. 18. As part of the agreed upon terms of the MoU for a totalof 250MW of future tidal power development, theinitial 50MW project could be scaled up to more than200MW of installed capacity. The project is expectedto cost around Rs 750 crore 19. Thank you