Tidal energy, also referred to as tidal power,is a process that harnesses the energy of the tides and converts it into power. Tidal energy is far more predictable than other forms of clean, green, renewable energy such as solar, wind and wave energy. In fact, tidal energy is far from being a new concept and has been used throughout history as a source of energy. The earliest account of tidal energy use dates back through the Middle Ages to Roman times!
How do the tides work? Basically, the relationship between the Earth and moon causes the tide to change. As the moon rotates around Earth and the Earth rotates around the sun, it has a gravitational push and pull on the ocean. This fluctuation takes energy, and that is the energy that can be harnessed! Because this process of fluctuating tides occurs at fairly predictable intervals of time, and because it is likely that the tidal fluctuations will continue to occur indefinitely, tidal energy is viewed as an inexhaustible resource.
There are several tidal energy farms throughout the world. Two farms are currently being built in Wales and both are expected to be operational in 2010. In Canada, the British Columbia Tidal Energy Corporation is currently building three turbines in Campbell River and should be completed by the end of 2009. Nova Scotia is also building a tidal energy farm.
Tidal energy power, like solar power, has a high initial investment and a very low maintenance cost. This poses a challenge, however, because many investors aren�t willing to provide the initial investment, especially when returns come back over an extended period of time. However, tidal energy has the potential to replace fossil fuel power plants. For example, a proposal for a tidal energy plant for the Severn Barrage in the United Kingdom would prevent eighteen-million tons of coal each year from being used.
There are many additional benefits to investing in tidal energy. To start, tidal energy farms can be located in any body of water that is affected by tidal fluctuation�oceans and rivers connected to the ocean. It is also very consistent, which is a problem that other sources of clean, sustainable energy sources face.
Harnessing tidal energy is a very interesting idea. Tidal energy advocates are highly optimistic and see the potential for tidal energy to provide a large amount of the energy. Opponents to the idea of tidal energy mainly point out its initial investment, which like solar power, is very high. However, many people are able to see beyond this challenge. After all, most environmentalists easily understand the concept of investing in compact fluorescent light (CFL) bulbs, even though they are more expensive than incandescent bulbs.
We need to keep in mind that when the use of fossil fuels began, it was extremely expensive to build the power plants and create the energy grids necessary to transfer that energy. More than one hundred years later, the process of obtaining energy from fossil fuels has been streamlined. EnviroCitizen.org acknowledges that it may be more expensive to invest in tidal energy now, but notes that in the not-too-distant-future we will be able to enjoy a low-cost, highly renewable, very green, clean energy source that with further preserve the Earth! An upfront investment is certainly worth the long-term benefits the Earth with experience.
Source : http://www.envirocitizen.org/article/how-does-tidal-energy-work/1087.html
Tidal Energy : Introduction
Tides are the waves caused due to the gravitational pull of the moon and also sun(though its pull is very low). The rise is called high tide and fall is called low tide. This building up and receding of waves happens twice a day and causes enormous movement of water. It is so powerful that it has caused many mishaps and resulted in sinking of ships. Thus tidal energy forms a large source of energy and can be harnessed in some of the coastal areas of the world. Tidal dams are built near shores for this purpose. During high tide, the water flows into the dam and during low tide, water flows out which result in turning the turbine.
Lets now discuss the advantages and disadvantages of tidal energy.
Advantages of Tidal Energy
1) It is an inexhaustible source of energy.
2) Tidal energy is environment friendly energy and doesn�t produce greenhouse gases.
3) As 71% of Earth�s surface is covered by water, there is scope to generate this energy on large scale.
4) We can predict the rise and fall of tides as they follow cyclic fashion.
5) Efficiency of tidal power is far greater as compared to coal, solar or wind energy. Its efficiency is around 80%.
6) Although cost of construction of tidal power is high but maintenance 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 higher than other renewable energy sources.
Disadvantages of Tidal Energy
1) Cost of construction of tidal power plant is high.
2) There are very few ideal locations for construction of plant and they too are localized to coastal regions only.
3) Intensity of sea waves is unpredictable and there can be damage to power generation units.
4) Influences aquatic life adversely and can disrupt migration of fish.
5) The actual generation is for a short period of time. The tides only happen twice a day so electricity can be produced only for that time.
6) Frozen sea, low or weak tides, straight shorelines, low tidal rise or fall are some of the obstructions.
7) This technology is still not cost effective and more technological advancements are required to make it commercially viable.
8) Usually the places where tidal energy is produced are far away from the places where it is consumed. This transmission is expensive and difficult.
Tidal Energy is thus a clean source of energy and doesn�t require much land or other resources as in harnessing energy from other sources. However, the energy generated is not much as high and low tides occur only twice a day and continuous energy production is not possible.
Keep Reading : http://www.ianswer4u.com/
The power of the rise and fall of the sea level or tidal power, can be harnessed to generate electricity.
Tidal Power
Tidal power traditionally involves erecting a dam across the opening to a tidal basin. The dam includes a sluice that is opened to allow the tide to flow into the basin; the sluice is then closed, and as the sea level drops, traditional hydropower technologies can be used to generate electricity from the elevated water in the basin. Some researchers are also trying to extract energy directly from tidal flow streams.
The energy potential of tidal basins is large � the largest facility, the La Rance station in France, generates 240 megawatts of power. Currently, France is the only country that successfully uses this power source. French engineers have noted that if the use of tidal power on a global level was brought to high enough levels, the Earth would slow its rotation by 24 hours every 2,000 years.
Tidal energy systems can have environmental impacts on tidal basins because of reduced tidal flow and silt buildup.
3 Ways of Using the Tidal Power of the Ocean
There are three basic ways to tap the ocean for its energy. We can use the ocean's waves, we can use the ocean's high and low tides, or we can use temperature differences in the water.
1. Wave Energy
Kinetic energy (movement) exists in the moving waves of the ocean. That energy can be used to power a turbine. In this simple example, (illustrated to the right) the wave rises into a chamber. The rising water forces the air out of the chamber. The moving air spins a turbine which can turn a generator.
When the wave goes down, air flows through the turbine and back into the chamber through doors that are normally closed.
This is only one type of wave-energy system. Others actually use the up and down motion of the wave to power a piston that moves up and down inside a cylinder. That piston can also turn a generator.
Most wave-energy systems are very small. But, they can be used to power a warning buoy or a small light house.
2. Tidal Energy
Another form of ocean energy is called tidal energy. When tides comes into the shore, they can be trapped in reservoirs behind dams. Then when the tide drops, the water behind the dam can be let out just like in a regular hydroelectric power plant.
In order for this to work well, you need large increases in tides. An increase of at least 16 feet between low tide to high tide is needed. There are only a few places where this tide change occurs around the earth. Some power plants are already operating using this idea. One plant in France makes enough energy from tides to power 240,000 homes.
3. Ocean Thermal Energy
The final ocean energy idea uses temperature differences in the ocean. If you ever went swimming in the ocean and dove deep below the surface, you would have noticed that the water gets colder the deeper you go. It's warmer on the surface because sunlight warms the water. But below the surface, the ocean gets very cold. That's why scuba divers wear wet suits when they dive down deep. Their wet suits trapped their body heat to keep them warm.
Power plants can be built that use this difference in temperature to make energy. A difference of at least 38 degrees Fahrenheit is needed between the warmer surface water and the colder deep ocean water.
Using this type of energy source is called Ocean Thermal Energy Conversion or OTEC. It is being used in both Japan and in Hawaii in some demonstration projects.
Source : http://inventors.about.com/od/tstartinventions/a/tidal_power.htm
Tidal energy, or tidal power, is a little known and little used energy source. Yet it is a very old energy source, dating back to the middle ages in Europe. Tidal energy is created by the relative motion of the Earth, Moon, Sun, and the gravitational interactions between them. Every coastal region has two high and two low tides in each approximate 24 hour period. A big advantage of tidal energy is its predictability. The size and time of tides can be predicted very efficiently.
Tidal energy is little used around the world. In order for electricity to be generated, differences between high and low tides must consistently reach 16 feet. There are few regions in the world where this occurs. There are currently no tidal energy facilities in the United States although there is potential in the Pacific Northwest and the Atlantic Northeast.
Harnessing Tidal Energy.
Barrage or Dam. There are only three barrage tidal plants in the world. Essentially, a barrage is built which forces tidal flows through turbines, creating electricity. When the water levels on both sides of the barrage are significantly different, gates are opened, allowing water to flow through and activate the turbines. The Rance Tidal Plant in France is a prime example of the barrage method of tidal energy.
Tidal Turbines. A relatively new technology, tidal turbines are very similar to wind turbines but underwater. They are positioned strategically at entrances to bays or rivers, among others, where currents are fast. Because seawater is much denser than air, a single tidal turbine can produce significantly more energy than a wind turbine of the same size.
Environmental Impact.
Tidal energy is a renewable resource, but the classic, barrage method of harnessing tidal energy has some negative environmental impacts. Most notably, tidal power plants upset fish migrations and, by disrupting water flows, can upset entire estuarine ecosystems. Tidal turbines however, because they do not block water flow, may be a viable answer to these concerns.
How Tidal Compares to Solar.
Tidal turbines are a very efficient source of energy, and that is an advantage over solar to this point. However, there are only 40 locations in the world where tidal power is feasible. The sun shines everywhere. Nonetheless, they are both certainly part of the solution. While I support solar energy wholeheartedly, tidal power could be a great source for green energy. Especially for northern coastal regions where the sun is not as prevalent. I live in Oregon and I�ve personally witnessed the dramatic turn of tides (I�m talking about starfish clinging on at eye-level during low tide!)
Source : http://solar.calfinder.com/blog/news/what-is-tidal-energy/
Tidal energy, also referred to as tidal power,is a process that harnesses the energy of the tides and converts it into power. Tidal energy is far more predictable than other forms of clean, green, renewable energy such as solar, wind and wave energy. In fact, tidal energy is far from being a new concept and has been used throughout history as a source of energy. The earliest account of tidal energy use dates back through the Middle Ages to Roman times!
