Energy is defined as the ability to do work, to define alternative energy there are many categories to be defined as solar energy, wind energy, Geothermal energy, Tides and Hydro electric energy.
Alternative energy is not based on burning of fossil fuels or the splitting of atoms, rather it is the undesirable effects of pollution seen today that come from both burning fossil fuels and also from nuclear waste byproducts.
Solar energy, wind energy, geothermal energy, Tides and Hydroelectric energy are all forms of positive alternative energies. They all have their own dimensions and descriptions on how they are used and are utilized.
Solar energy is one of the main sources of energy, it is said by the scientists that the total energy used by man equals to that of 35,000 energy received from the sun. The other fact is 1/3 of the energy received from the sun is absorbed by the outer atmosphere and is reflected back into space.
Solar energy is currently used in to heat up swimming pools or the furnaces for home at a small scale, it is used on a large scale to run cars, power plant and space ships.
Another alternative energy is the Wind power, which can be used without producing products that are harmful to the nature. Wind is highly dependable on weather and location hence the power that is produced when a windmill is facing the wind is around 50 watts. Windmill plays a greater role in generating electricity.
Geothermal energy is used to generate steam to run a steam turbine since its energy is obtained from the internal heat of the planet. Generating steam to run a steam turbine indirectly generates electricity, which becomes a useful source.
It is said that the power of tides can be used to produce electricity, which is similar to conventional hydroelectric dams. The reservoirs are filled due to the utilization of the natural motion of the tides.
Hydroelectricity is obtained from the damming of rivers and the utilization of the potential energy stored in the water. It is similar to the water stored behind a dam that released high pressure by which the kinetic energy is transferred into the turbine blades that is useful in generating electricity.
Although the hydro electricity system has enormous costs up front, but on the other hand it has relatively low maintenance costs by which the supply of power is cheap. In the United States around 180,000 MW approx of hydroelectric power is available.