Renewable Sources of Electricity

Electrical energy can be generated by using the renewable sources such as wind, sunlight, geothermal, hydropower and biomass. These energy sources are renewable, meaning that they can be replenished naturally. In comparison to fossil fuels that are commonly utilized for generating the energy, these renewable sources are eco-friendly. Another major advantage of renewable source is that they generate clean electricity without the emission of hazardous greenhouse gases. With the raising need of electricity and issues regarding the energy crisis, renewable energy sources are the future hope to meet the demand of worldwide population. It is estimated that about 50 percent of the energy generated from the renewable source is used to produce electricity.

Biomass
Biomass refers to any organic material derived from plants and animals. Humans have been using biomass for generating energy since long time. For example, wood biomass has been used to provide heat in many regions. It is still practiced in remote areas as the major source for cooking and heating. Apart from releasing heat, biomass can also be converted into electricity, biodiesel, ethanol and methane gas. Generation of electricity from biomass is commonly implemented in manufacturing industries, in which the leftover biomass like wood waste or paper waste is burnt first to produce steam, which is then used for producing the electricity.

Geothermal
Geothermal source is used less common as compared to other renewable sources. It refers to the energy present inside the Earth's crust. In order to generate electricity from geothermal source, deep wells are dug and water with high temperature or steam is pumped into the surface. Large hydrothermal (heated ground water) areas found naturally are called geothermal reservoirs. Geothermal power plants are built near hydrothermal reservoirs. Geothermal energy forms present on the Earth's surface are hot springs and volcanoes. Other than generating electricity, geothermal energy source is used for heating purposes.

Hydropower
Among the other renewable sources of electricity, hydropower is most commonly used. Electricity generation by using hydropower was discovered in the 1880s. The principle behind the working of hydroelectric power plants is to use mechanical energy of moving water (swift falling or descending water) to turn blades of a turbine, which in turn produces electricity. Since the source of hydropower is moving water, it is obvious that the power plants are located near the water source (either natural waterfalls or man-made dams). The more the amount and speed of flowing water, the higher is the electricity production.

Solar
Solar energy or sunlight is used commonly to convert into electricity and heat energy. For converting into electricity, there are two major methods, direct and indirect technique. In the former case, solar energy is converted directly into electricity by using solar cells or photovoltaic devices. In case of indirect conversion, solar heat harvested through solar thermal collectors is used to heat fluid and produce steam. The generated steam produces electricity by using generators. The disadvantage of solar energy is the variance in intensity depending upon the climatic condition and location.

Wind
Wind refers to moving air. The speed and/or velocity of wind is used to rotate blades, which then generates electricity with the help of a generator. Wind turbines or wind mills are installed, especially at the higher elevated areas in a particular orientation so as to harvest maximum wind energy. A series of wind farms installed for supplying electricity in a mass scale is called a wind power plant. Nowadays, many private companies have started the business of installing wind power plants to produce and sell electricity to large industries.

As per statistics, the use of renewable energy sources is increased tremendously in recent times. As of 2006, about 18 percent of the world's energy is derived from the renewable sources, with 13 percent accounting to biomass source. In fact, biomass is the major renewable energy source in the developing countries. However, major drawbacks of renewable sources are the high cost of producing electricity. More sophisticated techniques need to be introduced in order to combat this problem and make it available to the general public.