Non-conventional sources of energy from

sea

Tidal EnergyTidal power, also called tidal energy, is a form of hydropower

that converts the energy of tides into useful forms of power, mainly electricity, although not yet widely used, tidal power has potential for future electricity generation. Tides are more predictable than wind energy and solar power.

Generation of tidal energyTidal power is taken from the Earth's oceanic tides; tidal forces are

periodic variations in gravitational attraction exerted by celestial bodies. These forces creates corresponding motions or currents in the world's oceans. Due to the strong attraction to the oceans, a bulge in the water level is created, causing a temporary increase in sea level. When the sea level is raised, water from the middle of the ocean is forced to move toward the shorelines, creating a tide. This occurrence takes place in an unfailing manner, due to the consistent pattern of the moon’s orbitaround the earth The magnitude and character of this motion reflects the changing positions of the Moon and Sun relative to the Earth, the effects of Earth's rotation, and local geography of the sea floor and coastlines.

GENERATING METHODSTidal stream generator• Tidal stream generators (or TSGs) make use of the kinetic energy

of moving water to power turbines, in a similar way to wind turbines that use wind to power turbines. Some tidal generators can be built into the structures of existing bridges, involving virtually no aesthetic problems.

Tidal Barrage• Tidal barrages make use of the potent ial energy in the

dif ference in height between high and low t ides. When using t idal barrages to generate power, the potential energy from a t ide is seized through strategic placement of special ized dams. When the sea level r ises and the t ide begins to come in, the temporary increase in t idal power is channeled into a large basin behind the dam, holding a large amount of potent ial energy. With the receding t ide, this energy is then converted into mechanical energy as the water is released through large turbines that create electr ical power through the use of generators

Tidal Power IssuesEcologicalTidal power can have effects on marine life. The turbines can

accidentally kill swimming sea

CorrosionSalt water causes corrosion in metal parts. It can be difficult to

maintain tidal stream generators due to their size and depth in the water.

life with the rotating blades. Some fish may no longer utilize the area if threatened with a constant rotating or noise-making object

Wave EnergyWaves are generated by the wind as it blows across the sea surface.

Energy is transferred from the wind to the waves.Waves travel vast distancesacross oceans at great speed. The longer and stronger the wind blows over the sea surface, the higher, longer, faster and more powerful the sea is. The energy within a wave is proportional to the square of the wave height, so a two-metre high wave has four times the power of a one-metre high wave.

The Pelamis Wave Energy Converter is a technology that uses the motion of ocean surface waves to create electricity. The machine is made up of connected sections which flex and bend as waves pass; it is this

Wave Energy Converter

motion which is used to generate electricity.

Ocean thermal EnergyA very large area of sea is called an

ocean. The water at the surface of an ocean gets heated by the heat of the sun and attains a higher temperature than the colder water at deeper levels in the ocean. So, there is always a temperature difference between the water "at the surface of ocean" and" at deeper levels." The energy available due to the difference in the temperature of water at the surface of the ocean and at deeper levels is called ocean thermal energy (OTE). The ocean thermal energy can be converted into a usable form of energy like electricity.

Generating methods

The devices used to harness ocean thermal energy are called Ocean

deeper ocean is pumped up to cool the used up vapours and convert them again into a liquid. This process is repeated again and again.

Thermal Energy Conversion power plants (or OTEC power plants). A temperature difference of 20'C (or more) between the surface water of ocean and deeper water is needed for operating OTEC power plants. In one type of OTEC power plant, the warm surface water of ocean is used to boil a liquid like ammonia or a chlorofluorocarbon (CFC). The high pressure vapours of the liquid (formed by boiling) are then used to turn the turbine of a generator and produce electricity. The colder water from the

A great advantage of the ocean thermal energy is that it can be used continuously 24 hours a day throughout the year. Another advantage is that ocean thermal energy is a renewable source of energy and its uses does not cause any pollution.

Thank you!By Sonu Vincent (Tacitus)Stefan ThomasSurya AkashVraj ShahSyed Mohsin