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Energy Resources Energy is used for domestic purpose, agricultural purpose, production of industrial goods and for the transportation purpose. In fact

Dec 29, 2015

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  • Energy ResourcesEnergy is used for domestic purpose, agricultural purpose, production of industrial goods and for the transportation purpose. In fact per capita energy consumption indicates the development of any country.

  • Growing energy demand: The demand for the energy resources are increasing due to increasing population and increased pace of development in developing country especially India and China. Between 1950 and 1990, the worlds energy need increases four folds. Year (1965-2005)Rate of world energy uses in terra watts.

  • Source of energy:

    A source of energy is one which provide adequate amount of energy in a usable form over a long period of time. It is divided into two major type:

    Renewable resource: it can be regenerated continuously in nature and are inexhaustible: examples: wood, solar, wind, tidal, hydropower, biomass energy, bio-fuel, geothermal energy and hydrogen.

    Non-renewable resource: it include resources which accumulation in nature take place over a long span of time and once exhausted cannot be quickly replenished. Examples: coal, petroleum, natural gas, and fuels like uranium and thorium.

    Renewable Energy resource:

    a) Solar energy: The source of solar energy is the nuclear fusion reaction taking place in the sun where lighter hydrogen atom combine to form heavier helium atom. The luminosity of the Sun is about 3.86 x 1026 watts. This is the total power radiated out into space by the Sun. Most of this radiation is in the visible and infrared part of the electromagnetic spectrum, with less than 1 % emitted in the radio, UV and X-ray spectral bands. The power of the sun at the earth, per square metre is called the solar constant and is approximately 1370 watts per square metre (W m-2).

  • The energy of sun is harnessed from long time especially for drying purpose like seeds, clothes etc, however recently special instruments are use to harness the solar energy. Some of such instruments are:

    1) Solar cell: also known as photovoltaic cells or PV cells are made up of semi-conductor material like silicon and gallium. This material is dope with Boron or Phosphorous to generate N and P region to create an electric field. As the solar light absorbed in the cell and electron get released which then follow the electric field and generate the electricity. It is pollution free electricity generation process, however due to the high cost of raw material and variability of sun intensity it is not much popular yet.Mainly used in calculator, electronicWatches, street light, traffic signal, water pumps etc.

  • Solar cooker: mainly used for the cooking food and boiling water. It is mainly of three design: heat-trap boxes, curved concentrators (parabolics) and panel cookers. Food cooks best in dark, shallow, thin metal pots with dark, tight-fitting lids to hold in heat and moisture. Solar power plant: Solar energy is harnessed on large scale by using concave reflector which cause boiling of water to produce steam. The steam turbine drives a generator to produce electricity .Example: 50K Watt capacity solar power plant has been installed at Gurgaon.

  • Solar water heater: Solar heat is used to warm water by conversion of light into heat energy. Solar furnace: A solar furnace is a structure used to harness the rays of the sun in order to produce high temperatures. This is achieved by using a curved mirror (or an array of mirrors) acting as a parabolic reflector to concentrate light (Insolation) on to a focal point. The temperature at the focal point may reach up to 3,000 degrees Celsius, and this heat can be used to generate electricity, melt steel or make hydrogen fuel.

  • Wind energy: Utilized Kinetic energy of wind to generate electricity. The energy is harnessed by making wind mill. A large number of wind mill installed in cluster called wind farm.

    The wind energy potential of our country is estimated to be about 20,000 MW , while at present we are generating about 1020 MW. The largest wind farm of our country is near Kanyakumari in Tamil Nadu generating 380 MW electricity.

  • Advantage of Wind power:

    Pollution free source of energy. According to EPA estimates, running a 1 MW wind turbine for one year eliminates the following pollutants from entering the atmosphere: 1500 tons of carbon dioxide, 6.5 tons of sulfur dioxide, 3.2 tons of nitrogen oxides, and 60 pounds of mercury.

    Required little maintenance cost after the installation.

    Limitation of wind power:

    The power produced by a turbine is proportional to the wind velocity cubed. This means, at low wind speeds (i.e. 4 m/s), there is a significant drop-off in the power produced versus moderate wind speeds (i.e. 7 m/s).

    T he power produced is proportional to the swept area that mean it is proportional to the blade length squared.

    The wind farms are the source of noise pollution and also results into bird deaths due to bird strike on rotating wind mill blade.

    Mainly useful in the costal areas with high wind speed.

    High cost of per unit electricity compare to electricity generated from fossil fuels.

  • Hydropower energy:

    A hydraulic turbine converts the energy of flowing water into mechanical energy. A hydroelectric generator converts this mechanical energy into electricity. The operation of a generator is based on the principles discovered by Faraday.

    The present installed capacity of Hydropower as on 30-06-2011 is approximately 37,367.4 MW which is 21.53% of total Electricity generation in India.

  • Advantages to hydroelectric power:

    Fuel is not burned so there is minimal pollution. It plays a major role in reducing greenhouse gas emission.

    Relatively low operation and maintenance cost for hydropower.

    It's renewable - rainfall renews the water in the reservoir, so the fuel is almost always there.

    Disadvantages to hydroelectric power:

    disadvantage of hydropower is related to the construction of Dams which resulted into inundation of land and wild life habitat.

    Power supply depend upon the Hydrology (precipitation) so variation in rainfall event will affect the power generation.

    Dam construction affects the quality of reservoir and stream water.

    Displacement of local population.

  • Tidal energy: Ocean tides produced due to gravitational pool of sun and moon on earth surface. The energy is harnessed by using the difference in high tide (high water level) and low tide (low water level) in ocean. This energy is harnessed by constructing tidal barrage in costal areas such as bay and estuary. During high tide ocean water enter into the barrage reservoir and turn the turbine attached to produce electricity. In case of low tide, sea level is lower so water stored in the reservoir move out to ocean and again turn the turbine. High tideLow tide

  • Advantage of Tidal energy:

    Environmental friendly method of energy generation with no pollution emission.

    Tides are more predictable and can be predicted years in advance so reliable source of energy.

    Barrage construction help in protection against floods in costal area and also help in the transportation.Disadvantage of tidal energy:

    1) Only few suitable sites are present in world for harnessing the tidal energy. In India, two sites Gulf of Camby and Gulf of Kutch are producing tidal energy.

    2) High capital cost and intermittent power generation takes place.

    3) Change in the estuary ecosystem due to construction of barrage.

    4) Accumulation of silt in the barrage which may accumulate pollutant.

  • Ocean Thermal Energy (OTE): The surface ocean layer is more warmer than the deeper ocean layer in the tropics and this temperature difference is used to generate electricity in Ocean thermal energy conversion power plant (OTEC). Minimum temperature difference should we 20C or more for the OTEC power plant to work. OTEC system works as a heat engine with a low boiling point working fluid such as ammonia, which work between two temperature of deep and surface water. The working fluid circulate in the closed system taking heat from warm surface water and evaporated to run turbine and generate electricity and discharging heat to the cold water by help of heat exchanger. So it is a continuous electricity generation process.

  • Geothermal energy: The term geothermal comes from the Greek geo, meaning earth, and therme, meaning heat, thus geothermal energy is energy derived from the natural heat of the earth.The source of heat can be due to the fission of natural radioactive material present in rocks or molten lava come into contact of water reservoir. High temperature and high pressure stream fields are present below earth surface in many parts. In some part this high temperature streams come out naturally over the surface through cracks in the form of natural geysers such as Manikaran, Kullu and Sohna Haryana. Some time pipe has to drill through rock to bring this hot water on surface which in turn run turbine to produce electricity.

  • Biomass energy: Biomass is the organic matter produced by plant and animal in the form of wood, crop residue, cattle dung, manure, sewage etc. Biomass energy is of the following type:

    Energy plantation: Solar energy is trapped by green plants through photosynthesis and converted into biomass energy which can be trapped either by burning directly or by getting converted into burnable gas or fuel by processing. Example: Plantation of cottonwood, leucaena etc.

    Petro-crops: latex containing plants such as euphorbias and oil palms are rich in hydrocarbon and can yield fuel oil at high temperature