Non-Conventional Sources of Energy
Sources of Energy
Countries all over the world are facing twin problems of fast increasing demand for energy and limited supplies of and rapidly depleting conventional sources of energy like coal, petroleum, natural gas, wood and nuclear power. Under such circumstances, non-conventional sources of energy have assumed much importance: Solar energy, wind energy, geothermal power, ocean power, tidal energy and biomass energy are some of the outstanding examples of non-conventional sources of energy. These sources are renewable, clean and non-polluting.
Sun is the source of all energy on the earth and all other sources of energy are derived from energy received from the sun. The daily average global radiation is about 5 kwh per sq. m. per day with sunshine hours ranging between 2300 and 3200 per year. This amount of energy is much more than the total energy requirements of the world at the current level of consumption. Solar energy can be used for various purposes such as heating space and water. It also holds great potential for electric generation. Various applications of solar energy in the present day life are heating of domestic and commercial buildings, street lighting, food cooking by using solar cookers, power generation, agricultural and industrial operations, green house technology, desalination of water and generation of fuels like ethanol and hydrogen.
Tropical countries are lucky to receive sufficient amount of sun shine and can harness solar energy to their benefit. U.S.A., China, Japan and India are the major investors in developing technologies for the development of solar energy. However, desert areas with less clouds and more sunshine provide great opportunities for developing solar energy. Solar Ore located in the Mojave Desert in California (U.S.A.) is currently providing commercial electricity. Photovoltaic cell provides the best technology for harnessing solar energy as it provides clean and affordable energy. It is estimated that this technology has the potential to provide about 30% of the world’s electricity.
Wind blowing consistingly at high speed (usually between 25 and 35km/hr) in a particular direction contains great power which can be harnessed with the help of wind farms. A wind farm is a cluster of wind turbines which generate electricity through wind mills. The world’s largest wind farm is in Atlamont Pass in California. Scandinavian countries like Norway, Sweden, Finland, Netherlands etc. have great potential of wind energy. India is emerging as a major wind power producer in Asia while China has an ambitious plan to set up wind farms. The current installed capacity of wind power generators in the world is about 160 gigawatts (one gigawatt is equal to a thousand million watts). About 2% of the world’s electricity is obtained from wind energy.
This energy is obtained from the heat energy occurring in the earth’s interior. It is available to us in the form of hot water springs and geysers. The U.S.A., Iceland, Italy, Japan, New Zealand etc. are the main producers of this energy. The U.S.A. has the world’s largest geothermal power plant. The Geysers in California is the largest geothermal power plant in the world.
This energy is derived from plant synthesis and is one of the most versatile energy source which is capable of providing high quality gaseous, liquid and solid fuels. Wood and wood processing residues, crop residues, animal waste, seaweed etc. provide the basic raw materials for biomass energy generation. The main gases produced from biomass are methane, carbon dioxide, and hydrogen sulphide. Bio-diesel is made from vegetable oils. Biogas is the gas which is produced by fermentation of biodegradable materials like biomass manure, sewage, municipal waste, green waste etc. It mainly consists of methane and carbon dioxide. e gas obtained from the gasification of wood or some other biomass comprises mainly of nitrogen, hydrogen and carbon monoxide, with trace amount of methane. China, Netherlands and India are generating biomass energy.
Energy from Oceans
Tides and waves have great power which can be harnessed to generate energy. A tidal range of 3 meters is enough to generate energy. It is estimated that tides can produce 1100 gigawatts of energy in the world. About 30 places have been identified where tidal energy can be produced. Actual production is carried on at the mouth of Rauce river in North France, Kislaya Guba near Murmansk near the coast of the Barents Sea and in China. Fundy Bay in Canada and Severn Estuary in Britain have great potential for tidal energy. Waves have been used to produce energy in Japan, Norway and the U.S.A. Waves can produce about five times the energy requirements of Britain.
Sea thermal power can be generated if the difference between sea surface temperature and temperature at 1000-3000 m depths is at least 20°C. Such conditions prevail in the tropical zone and this zone holds great potential for generating sea thermal power. Efforts to harness this energy have been made in Cuba, U.S.A. (Miami coast and Hawaii islands) and Japan.