Renewable energy is important for replacing the energy generated by natural resource like petroleum, coal etc. Energy consumption from resource like oil and coal must be reduced because of the limited petroleum resources and contribute of pollution to the environment .Renewable energy having more importance due to increase in the cost of petroleum product and other product and the pollution caused by the use of these fossil fuels.Solar power has become a source of renewable energy and solar energy applications should be enhanced. Solar water heating system was a practical application to replace the using of electrical water heater. More research is needed to increase capability and reduce production costs of solar water heating system and make the solar water heating system more efficient and practical. Conversion of solar irradiance to Electrical Energy by PV Cells is the most promising future renewable energy. This energy is freely available and hence its distributed generation and use is a promising feature.