Today most of the people on the world using fossil fuels as primary energy for moving machine, electricity, cars, etc. Others then that familiar energy that we have been used is oil, gas, and coal.
Loss of use of fossil fuels is in addition to damaging the environment, as well as non-renewable and unsustainable. Fossil fuels are getting depleted and soon the fuel itself will run out. Now its time for looking for alternative energy out there.
An alternative energy from seawater could be applied, especially in country with lots of sea as one of their resources. Basically seawater not only producing food, but also fuels. Sea current are effected by earth and moon interaction. Based on that fact, we could build alternative energy from it.
Earth-Moon interaction energy is estimated to generate tidal currents every day by 3:17 TW, slightly larger than the installed power generation capacity worldwide in 1995 amounting to 2.92 TW (Kantha & Clayson, 2000).
The advantage of energy use in addition to ocean currents is environmentally friendly, energy intensity also has a large kinetic energy compared with other renewable energies. This is due to the density of sea water 830 times the density of air, so with the same capacity, ocean current turbines will be much smaller than the wind turbine. Another advantage is no need to design structures such as redundant power wind turbines that are designed to allow for the hurricane because of the physical conditions at a particular depth tends to calm and predictable.
Lack of energy of ocean currents are output to follow a sinusoidal graph according to the response of the tidal interaction due to motion of the Earth-Moon-Sun. At spring tide, the flow velocity will be very heavy, at high tide, the flow velocity will be reduced by approximately half of the tide. Another downside is the cost of installation and maintenance are quite large. Yet when the turbine is designed with the ocean currents tide conditions, i.e. when the flow velocity at which the smallest, and is designed to work continuously without reparations for five years, then this deficiency can be minimized and a huge economic advantage.
From PL studies Fraenkel (J Power and Energy Vol 216 A, 2002) an ideal location for the installation of power current flow velocity has two directions (bidirectional) a minimum of 2 meters per second. The ideal is 2.5 m / s or more. If one-way (river / stream geostropik) minimum 1.2-1.5 m / s. Depth of not less than 15 meters and not more than 40 or 50 meters. Relatively close to shore so that energy can be supplied at low cost. Sufficiently broad that it can be mounted more than one turbine and not the shipping or fishing.