A substance that is converted by process into usable energy then the substance is called source of energy. One of the beneficial factors for the use of the renewable energy is that it is naturally generated. These sources are constantly replenished such as sunlight, wind, heat and water. The common energy sources are Hydropower, Biomass, Biofuels, Wind, Geothermal and Solar Energy. It often includes commodities such as wood, paper and leather. The sources of renewable energy are present in the natural environment comprising the largest component of ecosystem. These sources are capable enough to replace the conventional sources of energy such as fossil energy by serving into distinct areas such as generation of electricity, Hot water/space heating, and the rural grid off energy services.

Meeting with the world wide expectation, renewable energy has evolved a lot. The use of renewable can be seen in day to day life basically in four areas electricity generation, air and water heating and cooling transportation and rural(off-grid) energy services. The existence of this energy has been find across wide geographical area as compared to other energy sources. Large application of renewable energy has resulted in significant improvement in energy security, climate change mitigation and economic benefits. The use of renewable energy has directed the people to move forward from conventional fuels due to the environmental reasons. Renewable energy can be defines as a form of energy derived from the natural sources which cannot be depleted such as wind or solar power.

Solar Energy is the most promptly accessible wellspring of energy. Sun is the sources of all energies, the primary forms of solar energy are heat and light. It doesn't have a place with anyone and is, in this manner, free. It is additionally the most essential of the non-conventional sources of energy. Since it is non-contaminating and along these lines, helps in decreasing the greenhouse impact. Solar energy can likewise be utilized to meet our power prerequisites. Through Solar Photovoltaic (SPV) cells, sunlight based radiation gets changed over into DC power specifically. Solar Energy is dependable progressing at Solar Transport. Fuel production is also done with the help of high temperature from solar energy. The energy is capture, which is produced at one time and is store for future use. Solar energy free and clean energy and the solar panels can be placed on roofs of houses which makes less occupancy.

The wind is a free, clean and gladly available renewable energy source. In the world, every day wind turbines are capturing the wind’s power and converting it to the electricity. The energy from the wind turns the two or three propeller-like blades around a rotor in windmill. The rotor is connected to the main shaft, and this shaft connected with the generator to create electricity. This source of power generation plays a progressively important role in the way of power in our world. Wind turbines captured the kinetic energy of the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) in the turbines generator or can be convert this mechanical power into useful power like electricity.

This form of energy is produced when the electricity generators are placed on the surface of the ocean. The energy is widely applied for the desalination purpose in the power plants and water pump. Output of the energy is calculated by the wave height, wave speed, wavelength and the water density. Energy generated by waves is converted into electricity through the electric generator. Wave movement is harnessed and converted to electricity. It’s a reliable source of energy as it can be harnessed enormously and there is no shortage. Depending on the method used for the capture of wave energy, it can be characterised into hydraulic ram, elastomeric hose pump, and pump to shore, hydroelectric turbine, air turbine and linear electric generator.

Geothermal energy is the heat from the Earth and it's a clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles under the surface of the earth, and down even deeper to the extremely high temperatures of molten rock named magma. There are three main types of geothermal energy systems: Direct use and district heating system and Electricity generation in power plants and geothermal heat pumps. The steam rotates a turbine, than the turbine activates a generator, which produces electricity.in the world, there are many power plants still use fossil fuels to boil water for steam. Geothermal power plants, using the steam, produced from reservoirs of hot water found a couple of miles or more below the Earth's surface. heat exchanger-a system of pipes covered in the shallow ground near the building.

One of the most prominent and promising renewable energy Biofuels can be converted directly to the liquid fuels. Biofuels is widely used for the transportation. There are various types of Biofuels such as Ethanol, Biodiesel, Bioalcohols, Green Diesel, and Biofuel gasoline, Vegetable Oil, Bioethers, Biogas, Syngas and Solid Biomass Fuels. Ethanol and Biodiesel are the commonly used biofuels. The main aim for introducing Biofuels was to replace Gasoline, Diesel Fuel and Coal. Green Diesel, Biogas. It is having enormous advantage when compared with the fossil fuels such as less greenhouse gases providing greater fuel securities. The use of Biofuel is widely dependent on the land availability. It is made from biological agents such as plant oils or animal through the set of chemical reactions.