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y Demand of electricity is increasing and global warming alsothreaten human life. It s time to move away from fossil fuel andother source

y The tides contain energy that can be harnessed to produceelectricity. Two types of tidal energy can be extracted. Kineticenergy can be harnessed from the ebbing and surging tides.Potential energy can be harnessed from differences in the highand low tides. Using tidal currents remains the primary methodof generating electricity.

y Tidal power has huge potential due to the size of the oceans andpredictability of the tides.

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y Tide is the periodic raising and lowering of average sealevel that occurs throughout the ocean of the world

y tidal energy , is a form of hydropower that converts theenergy of tides into electricity

y Tidal energy is one of the most important forms of renewable energy after solar and wind energy. tidal power will give us energy for billions of years to come.

y Tidal energy is a great source of clean renewable energy , but most of us don t know about how it works? Every day , the tide moves a huge amount of water twice , andharnessing it could provide a great deal of energy

Wha

tis Tidal Energy?

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Tidal energy is produced using tidal energy generators.This can be done in three ways

B arrage Tidal Plan t s

Tidal Turbines

Tidal Fence

Types of Tidal Plan t s

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Types of Tidal Plants

building a dam or a barrage , across a bay or estuary that has largedifferences in elevation between high and low tides. Water retainedbehind a dam at high tide generates a power head sufficient to generateelectricity as the tide ebbs and water released from within the dam turnsconventional turbines.

y Though they have proven very durabley barrage-style power plants are very expensive to

build and are fraught with environmentalproblems from the accumulation of silt withinthe dam catchment area (requiring regular , expensive dredging).

y Accordingly , engineers no longer considerbarrage-style tidal power feasible for energy generation.

y Low-cost power production at very large scale

B arrage Tidal Plan t s

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section of the lagoon wall showing the

movement of water through a turbine .

There are currently two commercial sized barrages in operation

240 MW turbine at La Rance , France16 MW plant at Annapolis Royal , Nova Scotia , Canada.

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Types of Tidal Plants

y Like the wind turbine , the tidal stream generatorrotates under water with the kinetic motions of theocean tides harnessing the energy to produceelectricity.

Tidal Turbines

Turbines installed in groups allowingfor more rapid, phased build-out

Power produced directly from tidalcurrents

Should be possible to generate power from tides with limitedenvironmental impact

Moderate-cost power production atvarying scales

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C omparison be tw een B arrage andTidal TurbinesBarrage In-stream Tidal

016,09-07-06,SNOPUD.ppt

Dam constructed across estuary

High cost ($ Bn)Long construction period (decade)

Power produced by closing dam athigh tide and allowing water to runthrough turbines once ocean hasreturned to low tide

Completely alters estuary circulationPower produced in twice-daily surgeAll attendant problems of hydro-electric dams

Low-cost power production at verylarge scale

Turbines installed in estuary at

constrictions in groups called arraysModerate unit cost ($ MM)Short unit construction time (weeks)

Power produced directly from tidalcurrents

More continuous (but stillintermittent) power production

Smart choice of turbines and layoutof arrays should avoid significantenvironment impact

Moderate-cost power production atvarying scales

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Tidal Po w er Advan t ages and Disadvan t ages

Advan t ages

O nce you've built it , tidal power is free.

It produces no greenhouse gases or other waste.

It needs no fuel.

It produces electricity reliably.

Not expensive to maintain.

Tides are totally predictable.

O ffshore turbines and vertical-axis turbines are not ruinously expensive to build and do not have a large environmentalimpact.

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Disadvan t agesy A barrage across an estuary is very expensive to build , and

affects a very wide area - the environment is changed formany miles upstream and downstream. Many birds rely onthe tide uncovering the mud f lats so that they can feed.Fish can't migrate , unless "fish ladders" are installed.

y O nly provides power for around 1 0 hours each day , whenthe tide is actually moving in or out.

y There are few suitable sites for tidal barrages

Tidal Po w er Advan t ages and Disadvan t ages

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y C onclusiony tides are a substantial potential source of clean renewable

energy for future human generations. Depleting oilreserves , the emission of greenhouse gases by burning coal , oil and other fossil fuels , as well as the accumulation of nuclear waste from nuclear reactors will inevitably forcepeople to replace most of our traditional energy sources with renewable energy in the future. Tidal energy is one of the best candidates for this

y Tidal power is a great source of renewable energy , but if it issteered in the right direction , it could play a vital role ingiving healthy energy to all. Development , innovation anda desire to make a change is needed if tidal power or any other renewable power to be adopted.

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THANK YOU