What are Tides?Tides are the rise and fall of thesea level’s surface. They arecaused by the gravitational pullof the Moon and Sun on thewater, and they can change atany time.One way we can benefit fromthis phenomenon is by using tidalenergy, which is a form ofhydropower.The amount of energy that isproduced is determined by howhigh or low the tide rises.
Tidal Power There are few types of Tidal Power but it all works on the same principal. http://www.youtube.com/watch?v=NO1mFMQlMDg
Tidal Streams/Tidal FencesFor most tidal energy generators,turbines are placed in tidal streams.A tidal stream is a fast-flowing bodyof water created by tides. There aregiant turnstiles that have verticalaxis turbines mounted on a fence.The water passes through the fenceand powers the turbines. They arealso known as Tidal Fences.
BarrageAnother type oftidal energygenerator uses alarge dam called abarrage. Barragescan beconstructedacross tidal rivers,bays, andestuaries. Tunnelsare builtthroughout thedam, and whenthe tide rises andfalls it turns aturbine thatgenerates power.
Tidal LagoonsThe final type of tidalenergy generatorinvolves the constructionof tidal lagoons. Tidallagoons might beestuaries or lagoons andhave fresh wateremptying into them. Atidal energy generatorusing tidal lagoons wouldfunction much like abarrage. Unlike barrages,however, tidal lagoonscan be constructed alongthe natural coastline.
Dynamic Tidal PowerDynamic tidal power (DTP) isone of the newest proposalsto harness the power oftides. Using DTP, enormousdams (as long as 50kilometers (31 miles)) wouldextend straight from theshore into the open ocean.
ADVANTAGES1) It is a renewable source of energy.2) Tidal energy is environment friendly energy and doesntproduce greenhouse gases.3) Because 71% of Earth’s surface is covered by water, it ispossible to generate this energy on a large scale.4) We can predict the rise and fall of tides as they followcyclic fashion.5) Efficiency of tidal power is far greater as compared tocoal, solar or wind energy. Its efficiency is around 80%.6) Although cost of construction of tidal power is high butmaintenance costs are relatively low.7) Tidal Energy doesn’t require any kind of fuel to run.8) The life of tidal energy power plant is very long.9) The energy density of tidal energy is relatively higherthan other renewable energy sources.
DISADVANTAGES1) Cost of construction of tidal power plant is high.2) There are very few ideal locations for construction of plant andthey too are localized to coastal regions only.3) Intensity of sea waves is unpredictable and there can bedamage to power generation units.4) Influences aquatic life adversely and can disrupt migration offish.5) The actual generation is for a short period of time. The tidesonly happen twice a day so electricity can be produced only forthat time.6) Frozen sea, low or weak tides, straight shorelines, low tidal riseor fall are some of the obstructions.7) This technology is still not cost effective and more technologicaladvancements are required to make it commercially viable.8) Usually the places where tidal energy is produced are far awayfrom the places where it is consumed. This transmission isexpensive and difficult.
Factors affecting Tidal Power Presence of Tidal Pattern. The difference between the flood tide and the ebb tide should be 4.6 m or higher. The volume of water moving around. The sites should be protected from natural hazards such as wave actions and storms, as they are destructive The site should not interrupt the flow of normal shipping traffic. The Sustainability of Marine Life is a major factor.
La Rance Tidal Barrage• The world’s first and second largest tidal power plant.• The construction of this barrage began in 1960. The system used consists of a dam 330m long and a 22km2 basin with a tidal range of 8m, it incorporates a lock to allow passage for small craft.• Supplies electricity to nearly 200,000 households
“I think that tidalenergy productionwill only be good if itis away from marinelife. You don’t wantthe poor fishies toget caught in theprocess”