Coastal Climate Action - Doing a little every day

Tidal Energy - Utilizing the Immense Power of the Oceans

Although it might seem like the stuff of science fiction, the tremendous power of the oceanic tides has been utilized by mankind for many years. The rise and fall of the tides is the result of the gravitational pull exerted on the earth by both the moon and the sun. These regular daily movements can be 'captured', and the resulting kinetic movement converted into electrical energy. The predictability of these tidal swells - causing two daily high tides and low tides in a regular cycle of just over 24 hours, makes Tidal Energy a truly renewable and virtually carbon zero energy source.

So How Does Tidal Energy Work?

In days gone by, the massive energy source produced by the moving tides was utilised by tidal mills and tidal wheels located along the sea shore. People found that by creating a barrier across the inlet or mouth of a tidal river it was possible to trap the rising tidal waters, and then direct them back through a water-wheel at low tide. This provided the energy for many uses, including grinding corn or stone, operating bellows in ironworks or large saws for lumber yards.

The system used today is not that different. In the simplest terms, the rise and fall of the tide is used to turn massive turbines and this turns kinetic energy into mechanical energy. This is then converted via a generator into electrical energy.

Another huge advantage of using this natural energy source is its reliability. With both a rise and a fall of the tides every 12 hours, this means that electricity can be generated with perfect regularity, unlike that of, say, wind power. Because of the tidal flow, the energy is generated during the rise/fall of the tides.

High tide signals the point of maximum electricity generation, with a lull at the point when the tide is turning (from low to high). This means that energy quotas can be determined many years in advance but the disadvantage is that this tidal generation may not coincide with high electrical demand.

The technology we use to create 'tidal energy' can be classified in two different ways. The first is similar to that used in traditional hydro-electric power generation. By using tidal barrages, electricity can be generated for the greater proportion of a 24 hour period.

However, it's extremely cost prohibitive to build fences and dams across a river estuary. Therefore this type of tidal energy is best gained in an area that has a natural narrowing of an estuary. This makes the size of the tidal barrier to construct somewhat shorter and less expensive.

The second type of technology is known as 'Tidal Stream Generation'. In essence, this is like a wind farm on the seabed with large turbine rotor blades that are turned by the water running across them. In areas of strong tide, the energy created from these is comparable to that of a wind turbine, but can be up to four times the size, so produce 400 percent more energy.

Advantages of Tidal Energy.

There are a great many plus points for using tidal energy. The first is its reliability. Compared to that of wind and solar energy, the power of the tides is far superior and constant. Also, because the turbines themselves are located underwater there is no sound or visual pollution.

Another advantage is that because no fossil fuels are burned during power generation there are no emissions into the atmosphere. It's also possible that large scale use of tidal energy could decrease the volume of nuclear power stations. Once the technology is put in place, tidal energy is essentially a free source of electricity generation.

Disadvantages of Tidal Energy.

Naturally, no kind of energy, renewable or otherwise, comes without some disadvantages. Those associated with tidal energy including the initial high costs to build power plants, place turbines on the sea bed and to dam and fence tidal estuaries. There is also a worry that these very actions might have an effect on aquatic life, ecosystems, the shoreline and also affect recreational activities as well as marine navigation.

The very reliable tidal flows also have a flip side, in that electricity generation is not very inflexible, only producing during extremely structured hours. Also, as the ocean can be an inhospitable place, the turbines and those who work there become at the mercy of the weather. Severe ocean conditions mean a high possibility of damages, and therefore support ships and repair teams need to be in place on a constant basis to carry out essential work whenever needed.

However, once the complete tidal energy system is in place, it's fairly inexpensive to operate producing electrical power without anyone noticing it. Also, tidal energy has negligible land use and large scale implementation of tidal power technologies could help stimulate declining shipbuilding and dockyard industries which could help fabricate these large metal bodied tidal energy devices.

Despite the challenges of harnessing the power of the sea and tides, 'Tidal Energy' is perhaps one of the most reliable and advantageous forms of renewable energy available today.

About the Author:

To learn more about 'Tidal Energy', or to explore the advantages and disadvantages of using Tidal Barrages as an alternative energy resource, visit today and find lots more good quality and free Alternative Energy Tutorials as well as information and articles about the many different types of alternative energy sources available for the home.

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By Peter Emson


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