ABSTRACT
Twice a day, thanks to a gravitational pull in the earth of our rotating moon, the oceans of the world produce powerful currents of water and the ascending and descending tides. Humans have studied and exploited the tremendous power of the tides for millennia, including harnessing the power of tides in tenth-century prey to spin mill wheels to grind flour. Forty years ago, the first tidal dams were built to convert tidal energy into electricity. One of the first dams of this type was built in the Bay of Fundy, in Canada, where the tides rise up to 12 meters (45 feet). Now new energy technologies (NO dams) that generate electricity from tidal currents could help produce as much electricity as the larger hydroelectric dams or nuclear power stations and fossil fuels without producing greenhouse gases or damaging the environment. This paper focuses on the need for renewable energy sources, the superiority of tidal energy over other types of renewable energy sources. The paper also gives brief information on construction, basic components and types of tidal power plants. Information is also given about turbines used in tidal plants. Advantages and disadvantages of tidal power plant is also discussed. The paper also includes the case study of La-Rance in France is given for more information on this important source of energy.
INTRODUCTION
Creating power using the flow of water is not a new idea. A Frenchman known only as Monsieur Girard presented the first patent for a wave energy device on July 12, 1799. He thought that if someone used the "movement and successive inequality of the waves, which after having been raised like mountains They fall into the next instant ... One has conceived the idea of the most exaggerated machine that has ever existed "(Ross 1991). This simple but inventive idea has changed drastically since its introduction. Today, hydropower, or energy produced by water, is used in various forms ranging from dams to tidal generation.
The sources for 90% of the electric energy generated today are non-renewable (Edinger 2000). Renewable energy sources are necessary because the earth will eventually run out of resources to create non-renewable energy. There are three types of renewable energy sources: solar, wind and hydro. Both solar and wind energy are drastically affected by weather variations, while tidal energy varies little when the weather changes. Sea water is 832 times as dense as air; Therefore, the kinetic energy available from an ocean current of 5 knots is equivalent to a wind speed of 270 km / m (Blue Energy Canada 2000). Thus, tidal power generation may be the most viable of all three types of renewable energy sources.
Advantage
1. No pollution
2. Renewable resources
3. More efficient than wind due to water density
4. Predictable source of energy versus wind and solar
5. The second generation has very few disadvantages
5.1. Does not affect wildlife
5.2. Does not affect silt deposits
5.3. Less expensive - both in construction and maintenance
Disadvantages
1. Currently expensive
1.1. Expensive to build and maintain
1.2. A 1085MW installation could cost up to $ 1.2 billion to build and run
2. Connection to the network
3. The technology is not fully developed
4. Barrage style only produces power for about 10 hours out of the day
5. The barrier style has environmental effects
5.1. As the migration of fish and plants
5.2. Sediment deposits
5.3. Changes in local tides: still under study
BASIC PRINCIPLES OF TUESDAYS
Gravitational Effects and the Centrifugal Force: The interaction of the Moon and the Earth causes the oceans to jump towards the Moon, while on the opposite side the gravitational effect is partially protected by the Earth resulting in a slightly smaller interaction and The oceans lit That side is bulging out of the Moon, due to centrifugal forces. This is known as the Lunar Tide. This is complicated by the gravitational interaction of the Sun resulting in the same effect of bulging towards and away from the Sun on opposing and opposing sides of the Earth. This is known as the solar tide. As the Sun and Moon are not in fixed positions in the celestial sphere, but change position with respect to each other, their influence on the margin (difference between low tide and high tide) is also affected. For example, when the Moon and the Sun are on the same plane as the Earth, the tide range is the overlap of the range due to lunar and solar tides. This results in the maximum tide margin (spring tides). Alternatively when they are at right angles to each other; Lower tidal differences are experienced resulting in neap tides. Basics of the tides
1. Most localities have two tidal cycles per day: 12 hours, 25 minutes
2. Essentially caused by the interaction of the centrifugal forces of the moon, earth and sun
3. Daytime tides are generated because the maxima and minima in each daily rotation are unequal in amplitude Facts of the waves:
• The waves are caused by a series of forces, ie wind, gravitational pull from the sun and moon, changes in atmospheric pressure, earthquakes, etc. The waves created by the wind are the most common waves. Uneven warming of the earth's surface generates wind, and wind blowing on water generates waves.
• This energy transfer results in a concentration of the energy involved: the initial solar energy level of approximately 1 kW / m2 is concentrated to an average wave power level of 70 kW / m peak length. This figure amounts to an average of 170 kW / m peak length during the winter, and to more than 1 MW / m during storms.
• Wave energy performance measures are characterized by diffuse energy, enormous forces during storms and variation over a wide range in wave size, length, period and direction.
• Wave energy is an irregular and oscillating low frequency energy source that must be converted to a frequency of 60 Hertz before it can be added to the mains.