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Tidal power
From CopperWiki
Tidal energy is the result of the sun and the moon’s gravitational pull on the tides. When the earth rotates, the tides move – ebbing and flowing. The change in the water level between high tide and low tide creates tidal currents in coastal areas, which can be forceful enough to drive a turbine. As tidal currents are governed by the movement of the earth, moon and sun, they are cyclical and completely predictable. This makes it favoutable for production and maintenance planning.
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[edit] Why should I be aware of this?
Not much progress has been made with regard to today power generation. Currently we are not able utilize it for maximum benefits but in near future, tidal power will be one of the important source of electricity generation.
Tidal power has great potential for future power and electricity generation because of the massive size of the oceans. The tide moves a huge amount of water twice each day, and harnessing it could provide a great deal of energy. Tidal power has a distinct advantage other renewable resources like wind and solar power since one can safely predict the coming and going of the tide.
However, research into the environmental impacts of tidal power is limited. There is concern that the use of tidal power can result in the silting up of waterways and fish are killed as they swim through the turbine blades. History has shown that there are always consequences for an ecosystem when humans alter the natural balance of an environment.
[edit] Tidal power and environment
There are two types of energy systems that can be used to extract energy:
- Kinetic energy - the moving water of rivers, tides and open ocean currents;
- Potential energy - from the difference in height (or head) between high and low tides.
Because of the lower ecological impact, generating energy from tidal currents is gaining in popularity over potential systems that are similar to dams sometimes called barrages or tidal fences. Generating energy through tidal currents uses turbines in a similar way to underwater windmills.
Many coastal sites worldwide are being examined for the suitability to produce tidal (kinetic) energy. Sites that are suitable exhibit high water speeds which typically occur in channels such as the entrances to bays, rivers of between islands where water currents are concentrated.
[edit] All about tidal power
The resource used to run the turbines is available totally free of cost - namely tidal waters.
[edit] The process
A dam is to be built across a river mouth or inlet. As the tide comes in the water is stored in the dam. When the tide goes out the water in the dam is channeled through pipes to turn the blades of a turbine. The turbine then turns a generator shaft and electricity is generated.
Tidal generation differs from hydroelectric plants where water flows only in one direction. The aim of tidal generators is to take advantage of both incoming and outgoing tides.
[edit] Orbital mechanics of the solar system
The potential of tidal power for electricity generation is immense as the tides are caused by the orbital mechanics of the solar system and are considered inexhaustible. In Europe, tide mills have been used for nearly a thousand years, mainly for grinding grains.
A tidal power scheme is a long-term source of electricity. A tidal barrage, if built, has been projected to save 18 million tons of coal per year of operation. This decreases the output of greenhouse gases into the atmosphere. More importantly, as the fossil fuel resource is likely to be eliminated by the end of the twenty-first century, tidal power is one of the alternative source of energy that will need to be developed to satisfy the human demand for energy.
[edit] Disadvantages
- Tidal power plants can't be set up anywhere at will as they are dependent on availability of regular tides of high range and sufficient cubature. They are also very expensive to set up.
- The high cost of setting up tidal power plants can often offset the advantage of having free tidal water. However, once the plant is up and running, only maintenance costs are applicable
The degrading effects of tidal power plants on the environment are not very clearly understood and still a lot of research is required to delve deeper into the issue
[edit] CopperBytes
- Water has been used by humans as an energy source in the form of tide mills and water wheels for nearly 2,000 years.
- Tidal turbines capture the energy of the currents, as well as that of rivers, irrigation canals, dam tailraces, and possibly even ocean currents such as the Gulf Stream.
- Wave and tidal energy, known collectively as “marine energy,” is currently capable of supplying electricity equivalent to 10–25% of today’s world’s production, according to various estimates, or about 2–5% of end-use energy.
- For purposes of energy capture, water is similar to wind, except that seawater is more than 800 times denser than air, essentially making it easier to capture energy.
- Whereas the wind can come from any direction, in most locations the tides flow only in and out, reducing the complexity of the mechanisms required to harvest that energy. [1]
[edit] References:
- Tidal power - energy from the sea
- Tidal Power Plants – Benefits and Disadvantages
- Benefits of tidal power generation
