renewable sources of energy

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Renewable sources of energy

Renewable sources of energyEnergy sourcesEnergy is the primary and most universal measure of all kinds of work by human beings and natureThe flow of energy is one of its formsDivided into 3Primary energy sourcesSecondary fuelsSupplementary sourcesPrimary energy sourcesA source which provide net supply of energyEg coal, oil, uraniumThe energy required to obtain from these fuels is much less than what they can produce by combustion and nuclear reactionTheir energy yield ratio is very high yield ratio the energy fed back by the material to the energy received from the environmentThis can only accelerate growth, but supply is limitedIt becomes very essential to use these fuels sparinglySecondary fuelsProduce no net energyBut they necessary for economyIntensive agricultural is an example, where in terms of energy the yield is less than the inputSupplementary fuelsNet energy yield is zeroBut they require highest investment in terms of energyThermal is an example

Coal, natural gas , oil and nuclear energy using breeder reactor are net energy yieldersSolar energy, wind energy, water energy are secondary sources of energySolar energy can be used through plants, solar cells and solar heaters.Geothermal and ocean thermal other sources

Energy sources and their availabilityCommercial or conventional energy sourcesMajor sources fossil fuelsWater power or energy stored in waterEnergy of nuclear fissionMinor sourcesSunWindTides in seaGeothermalOcean thermal electric conversionFuel cellsThermionicThermoelectric generatorsWood was dominant in pre industrialization era.Percentage use of various sources for the total energy consumption in the world

coal32.5% 92%Oil38.3%Gas19.0%Uranium0.13%hydro2.0%Wood6.6% 8%Dung1.2%waste0.3%Coal

Since the advent of industrialization coal has been the most common source of energy.Last 3 decades it is switched to oilCoal developed from vegetable matter which grew on past geological ages.trees and plants falling into water, decayed and producing peat bogs. These bogs are buried under layers of silt,due to soil pressure,heat and movement of earth crust distilled off some gaseous matter in bog and form brown coal or lignite, continuing this activity and reducing gaseous content progressively , forming peat lignite, bituminous and anthracite.

Oil Almost 40% of the energy needs of the world are fed by oilRising prices of oil making little strain on economyBut, with todays consumption and a resource amount of 250000million tones of oil, which is sufficient for about 100 years Refining petroleum or crude oils produce our fuel oilsThe potential oil bearing areas are located in Assam, Tripura , Manipur, West Bengal , Ganga valley, Punjab, Western coastal area,Gas Incompletely utilized at present and huge quantities are burned off in oil production processTransportation cost is hugeClassified asGases of fixed composition such as ethylene, methane..Composite industrial gases such as producer gas , coke oven gas, water gas , blast furnace gas etc.Agricultural and organic wastesat present a small amount of these are utilized for energy purposeMost of the unused material will cause considerable environmental problems.11Major points considered when using this source isThe waste should utilized near the source, in order to reduce the transportation costAppropriate equipments for burning or extracting energy from materials should be developed to suit local conditions and meet the requirements of the local areasOther non energy uses of the material should also be consideredConsidering the availability and the location of the material produced, these are regarded as an important energy supply for the rural areas.

Water powerDeveloped by allowing water to fall under the force of gravity.Used extensively for electric power generationPotential energy of water is converted to mechanical energy by using prime movers known as hydraulic turbines.It is quite cheap because of abundant availability of waterCapital cost is very high but operating cost is lowNo fuel requiredNuclear powerAccording to modern theories of atomic structure, matter consisting of minute particles known as atomsBetween them have a large binding energyControlled fission will release this energyThe energy released by the complete fission of 1kg uranium is equal to the heat energy obtained by burning 4500 tons of coal or 2200 tons of oil.

Non conventional sourcesBecause of large energy requirements and utilization, fossil fuels are exhausted eventually in futureIndustrialized countries put their concentration on renewable energy sources, some of them are

Solar energyWind energyEnergy from biomassOcean thermal energyTidal energyGeothermal energyHydrogen energyFuel cellsMagneto hydro dynamics generatorThermionic converterThermo electric power

Solar energyEnergy comes to the earth from sun This keeps the temp. of the earth above that in colder space, cause current in atmosphere and in ocean, cause water cycle and generate photosynthesis in plantsSolar power where sun hits to atmosphere is 10^17 W, that to earths surface is 10^16WThe world wide power demand is 10^13 WThe energy radiated by the sun on a bright sunny day is approximately1kW/m^2, this can be utilized to generate steam , and used to drive prime movers in the case of generation of electric energy.But their use is limited because of some reasons like, they required large space, uncertainty of availability of energy at constant rate due to cloud, wind etc

Applications of solar energy which enjoying success today are,Heating and cooling of residential buildingSolar water heatingSolar drying of agricultural and animal productsSolar distillation on a small community scaleSalt production by evaporation of sea water Solar cookersSolar engines for water pumpingFood refrigerationBio conversion and wind energy, which are indirect source of solar energySolar furnacesSolar electric power generation by-Solar pondsSteam generators heated by rotating reflectors or by tower conceptReflectors with lenses and pipes for fluid circulation12. Solar photovoltaic cells

Wind energyEnergy of wind can be economically used for electric power generationWinds are caused from-Heating and cooling of atmosphere which generates convection currents. Heating is caused by the absorption of solar energy on the earths surfaceThe rotation of the earth with respect to atmosphere and its motion around the sunThis is an indirect form of solar energy, used to run windmill, which in turn runs a generator to produce electricityIt can generate an estimated amount of 1.6*10^7MWSome types of windmills are- multi blade type windmillSail type windmillPropeller type windmillSavonius type windmillDarrieus type windmill

Some characteristics of wind energy are-It is a renewable source of energyLike all forms of solar energy ,wind power systems are non polluting , there is no adverse effect on environmentWind energy systems avoid fuel provision and transportOn small scale , it is less costly, for large scale, costs be competitive with conventional electricity and lower cost could be achieved in mass production

Problems associated with wind energyWind energy available in dilute and fluctuating manner, because of this reason conversion machine have to be necessarily largeUnlike water energy, wind energy need storage means because of its irregularity.Wind energy systems are noisy in operation, a large unit can be heard many kilometers away.Large areas are needed to install wind farms for electrical power generation.Energy from biomass and biogasThe potential for application of biomass as an alternate source of energy in India is greatWe have plenty of agricultural and forest resources for biomassIt is produced in nature through photosynthesisIt is an organic matterEnergy released by burning biomass is approximately 112kcal/mol ie, 469kJ/moleIt can be used directly by burning or can processed to produce convenient liquid and gaseous form

Biomass resources categorized into 3,In its traditional solid mass (wood and agricultural residues)In its non traditional form (converted in to liquid form)Ferment biomass anaaerobically to obtain a gaseous fuel called biogasBiomass resources includeConcentrated waste municipal solids , sewage wood products , industrial wastes, manure of large lotsDispersed waste residue crop residue, legging residue,disposed manureHarvested biomass, standby biomass, biomass energy plantation Energy plantationFor large scale production of electric power, can use fire wood as a fuelFor that selected species of trees are planted and harvested in regular period of time for large area , near to the plant,In India , suggested trees are eucalyptus, casuarina and baboolBiogas Main source of production biogas is wet cow dung, livestock wasteIn India, we have large cattle population, its population is 250millionOther sources areSewage , crop residue , vegetable wastes, poultry wastes ,

In big cities , sewage source is the main source for the production of biogas, and which is used to run pumps to pumpout the sewage water itselfThe sewage biogas contain 84% in rural areas, biogas can be used for cooking, lighting, mechanical power and small electricity generation.

Ocean thermal energyIndirect method of utilization of solar energyLarge amount of solar energy collected and stored in tropical oceansTropic oceans- equatorial band between the tropic of cancer and the tropic of CapricornIncluding central portions of pacific and Atlantic oceans, and most of Indian ocean They play a critical role in regulating earths climate and large scale weather patternThus, heat contained in oceans could be converted into electricity by utilizing the fact that the temperature difference between warm surface waters of the tropical oceans and the colder waters in the depth