Sources of alternative energy are the ones that can be used as an alternative to the energy sources or fuels used now- a-days. Sources of alternative energy are many and so are their uses. Alternative sources of energy are used because they are easily and freely available.
Wood was earlier considered to be an alternative source of energy because it was abundantly available and it was thought that the forest cover on this earth will never cease to exist. However, with the increase in deforestation, wood is not used an alternative source of energy any longer though it is used in place of oil many a times.
Hydro electric energy is the alternative energy generated from running water in the form of electricity. However, like wood hydro electric power cannot be said to be a true source of alternative energy. The reason is that all the reservoirs in which water is stored to generate electricity eventually get filled with sediment. Because of this a dam site can generally be used only once.
The fuel cells are another source of alternative energy that is being developed. It is used for producing electricity without causing any pollution. Fuel cells release water as the only waste product. The use of fuel cells is made in vehicles and electricity generation plants. Fuel cells are a promising source of alternative energy provided they are used wisely.
Alternative sources of energy are a viable option as energy sources that can efficiently and cost effectively meet the energy requirements of the present day and will continue to do so in the future.