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How Does Tidal Energy Work

By Editorial Dept | Fri, 24 July 2009 12:48 | 4

How Does Tidal Energy Work


Tidal energy is energy obtained from changing sea levels (the tide moving from high to low and vice versa.) This renewable energy source has great potential as tides are much more predictable than wind power and solar energy which are not at all consistent (seasons, bad weather, etc...)

There are three main ways to harness tidal power, these are:

Tidal Turbines


Tidal turbines use similar technology to wind turbines, although their blades are much shorter and stronger. So a good way to think of them is as underwater windmills. Basically the water currents turn the turbines, which in turn activate a generator that produces electricity. These systems work best where there are very strong tidal zones (Norwegian and British coastlines.) and although it is still in it’s infancy it does show great promise.
The upfront cost of these tidal stream systems is very high and also installation and maintenance is difficult. But it’s still cheaper and has less environmental impact than another tidal system which uses barrages.

Tidal Barrages


Tidal barrages are very similar to the Dams in hydroelectric plants, except that they are much larger as they are built across an estuary or bay. The tidal range (difference between high and low tide) needs to be in excess of five metres for the barrage to be workable. As the tide comes in, water flows through the dam into the basin. Then when the tide stops the gates are closed, which traps the water in the basin/estuary.
As the tide goes out gates in the dam which contain turbines are then opened and the flowing water passes through the turbines, thus generating energy.
Tidal barrages have very high infrastructure costs and are very damaging on the local environment. Also construction of such dams is a very lengthy project. A good example of this is the La Rance barrage in France which took over five years to build (it’s the largest tidal power station in the world.)

Tidal Lagoons


Tidal Lagoons are similar to barrages but have a much lower cost and impact on the environment. They are self contained structures cut off from the rest of the sea.
It works in pretty much the same way as a tidal barrage as when the tide rises the lagoon fills and when it falls the water is then released through the turbines.

The Pros and Cons of Tidal energy

 

Pros


• Tides go in and out twice a day. They are reliable and easy to predict, so it’s easy to manage positive spikes in energy.
• It’s completely renewable
• It produces no emissions

Cons


• Upfront capital costs are very high as most of the schemes require massive concrete constructions.
• Tidal power stations only generate electricity when the tide is flowing in or out (ten hours a day)
• Widespread environmental and ecological damage to the aquatic ecosystem.
• Equipment can be damaged by the strong currents and freak waves.

Written for OilPrice.com = the no.1 source for oil prices and crude oil information

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  • Anonymous on May 04 2010 said:
    Tidal turbines seem promising. They would need to be below the depths of shipping in channels between coasts cusing fast tidal flows. Because of the depths they would be largely immune from rough sea effects. Tbhey would anchor to heavy concrete, rquiring the sort of holding that a large ship anchoh has, Connection to shore by sub seas cables. Opportunities providing these conditions are limited but where they exist go go go.!
  • Anonymous on November 25 2010 said:
    A major drawback of tidal power stations is that they can only generate when the tide is flowing in or out - in other words, only for 10 hours each day. However, tides are totally predictable, so we can plan to have other power stations generating at those times when the tidal station is out of actionCommodity Tips Free trial
  • Anonymous on May 25 2011 said:
    If these turbines were installed in rivers, then the power generation would be continuous.Tidal power generation is equally important, but power generation in rivers has decided advantages.Equipment and machinery installed in oceans is difficult to control, the water is corrosive, and unusual weather presents more severe obstacles than rivers. The mathematics involved in designing river power generation would not have to account for as wide an amount of safety factors. Also, power generation in rivers can be located far inland, or almost any location within an area provided there is sufficient river current.Good luck.Paul Tyler, 17 Wood Lane, Maynard, MA 01754Tele: (978) 897-1901
  • joshrees on June 30 2014 said:
    this is good for all thank you for the info

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