The Emergence of Tidal Energy

With the limited supply of natural gases, engineers have started to create renewable energy. Renewable energy is energy that comes from naturally replenishing sources like the sun, wind, and water. Fossil fuels and non-renewable energy can only be used once, whereas renewable energy can be used over and over again. Fossil fuels and renewable energy have finite resources, but renewable energy has infinite resources. Gasoline is an example of a fossil fuel and non-renewable energy. Once the gasoline is burned, there is no way to get that energy back. Dams, solar panel, and wind turbines are all examples of renewable energy. Renewable energies can reuse their energy.  Recently engineers have created a new type of renewable energy: tidal energy.

Tidal energy uses the movement of water to create electrical energy.  The article “Underwater Tidal Power” defines tidal energy as “the power of electricity generation achieved by utilization of the variations in sea level caused primarily by the gravitational effects of the moon, combined with the rotation of the Earth by capturing the energy contained in moving water mass due to tides.” Tides are the rises and fall of sea levels, which creates tidal waves. The variation of sea levels is caused by the combined effect of the gravitational forces exerted by the moon and sun, and the rotation of the Earth. Also waves are created by wind, changes in atmospheric pressure, and earthquakes. “Waves created by wind are the most common waves,” according to the article.

Tidal energy has both kinetic and potential energy. Tidal kinetic energy comes from the current between ebbing and surging tides. Surge tides are the flowing forth of the tide from high to low water, and ebb tides are the flowing back of the tide from high to low water. Tidal potential energy comes from the difference in height between high and low tides. Engineers have designed various types of tidal plants using both kinetic and potential tidal energy.

All tidal plants use a turbine to transfer tidal energy to electrical energy. Turbines make electricity by having their blades rotate. Tides create a movement of water; that movement of the water turns the turbine blade and creates mechanical energy. As the blade rotates the turbine transfers mechanical energy, which was created from the tidal energy, to electrical energy.

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Engineers have created a variety of different tidal power plants to accommodate the different tides. There are three types of tidal plants based on the article, which are the following;

1. Tidal Fences: Turnstiles built between small islands or between mainland and islands. The turnstiles spin due to tidal currents to generate energy

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2. Barrage Tidal Plants: Barrage tidal plants are the most common type of tidal plant. Using a dam to trap water in a basin, and when reaches appropriate height due to high tide, release water to flow through turbines that turn an electric generator.

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3. Tidal Turbines: Look like wind turbines, often arrayed in rows but are underwater. Tidal currents spin turbines to create energy.

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Tidal power plants have both advantages and disadvantages. A major advantage of tidal plants is that they produce a very large amount of power. In fact, one tidal plant can produce the same amount of power as three nuclear power plants. The only downfalls for tidal plants are that they are extremely expensive to build and maintain. An example in the article states, “A 1085MW facility could cost as much as 1.2 billion dollars to construct and run.” Although the cost to construct and run the plant is highly expensive, the payoff of the massive amount of power created will cover those expenses. The emergence of tidal energy can positively impact business, the environment, and society.

 

http://www.mechanicalengineeringblog.com/3473-underwater-tidal-power-second-generation-tidal-power-plants-generating-electricity-from-ocean-waves/

-Mike Brown
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