Tidal+energy+-+Vivien

=Physics 11.4 presentations  = =**~TIDAL ENERGY~** = **What is Tidal Energy?** **Tidal energy** (tidal power) is a form of hydro-power that converts the energy of tides into electricity or other useful forms of power. It is one of the oldest forms of energy used by humans. Dated back to 787 A.D. tide mills were used on the Spanish, French and British coasts. Tidal power is the only form of energy which derives directly from the relative motions of the Earth-Moon system.

**SeaGen** - World's first commercial tidal generator (Strangford Lough Northern Ireland)  SWANTURBINES

The **"Swanturbines"** design is different to other devices in a number of ways. The most significant is that it is **direct drive**, where the blades are connected directly to the electrical generator without a gearbox between. This is **more efficient** and there is no gearbox to go wrong. Another difference is that it uses a **"gravity base"**, a large concrete block to hold it to the seabed, rather than drilling into the seabed. Finally, the blades are fixed pitch, rather than actively controlled, this is again to design out components that could be unreliable. HOW DO THEY WORK? ** These large underwater turbines are placed in areas with high tidal movements, and are designed to capture the kinetic motion of the ebbing and surging of ocean tides in order to produce electricity. When the tide comes in, the turbines turns due to the flow of water, and generates electricity. **LA RANCE TIDAL POWER PLANT ** La Rance tidal power plant is located near Mont Saint Michel, France since 1966. As the **largest tidal power plant**, it has been a very reliable source of electricity for the country. During the first 30 years of operation, the 24 turbines of the Rance facility has operated without major incidents or breakdowns for 160,000 hours and generated. The power plant generates annually **600 million kWh** using its 24 turbines of 10MW, or about 68MW average power, which is **0.012%** of the power consumed by France. In total, the plant cost roughly **94.5 Million Euros**.


 * The Energy Changes Involved:** __**Gravitational Potential Energy (Tides) >> Kinetic Energy >> Electrical Energy**__




 * FACTS AND FIGURES **
 * Tidal stream systems make use of the kinetic energy of moving water to power turbines, in a similar way to windmills that use moving air. This method is gaining in popularity because of the lower cost and lower ecological impact compared to barrages.
 * Tidal range may vary over a wide range (4.5-12.4 m) from site to site. A tidal range of at least 7 m is required for economical operation and for sufficient head of water for the turbines.
 * The world's most powerful tides occur in the upper reaches of the Bay of Fundy, where tidal ranges up to 17m.

** ADVANTAGES ** ** DISADVANTAGES **
 * ENVIRONMENTAL EFFECTS **
 * Predictable, reliable
 * Renewable
 * Non-polluting
 * The main environmental impact of turbines is their impact on fish. If the turbines are moving slowly enough, such as low velocities of 25-50 rpm, fish kill is minimalised and silt and other nutrients are able to flow through the structures.
 * Visual beauties
 * There is a high capital cost for a tidal energy project, with possibly a 10-year construction period.

**CITATION: ** http://www.swanturbines.co.uk/ http://www.google.com/ http://www.oceanenergycouncil.com/index.php/Tidal-Energy/Tidal-Energy.html http://en.wikipedia.org/wiki/Tidal_power http://home.clara.net/darvill/altenerg/tidal.htm http://www.thecanadianencyclopedia.com/index.cfm?PgNm=TCE&Params=A1ARTA0008003 http://www.leonardo-energy.org/worlds-largest-tidal-power-plant-almost-40-years-young