Conventional and Non-Conventional Sources of Energy 1. Electricity generation from Conventional Sources of Energy Conventional energy sources are the sources which are abundantly used for power generation. The sources mainly include coal, petroleum, natural gas, water and nuclear sources. This energy sources are exhaustible except water which is renewable source of energy. Electricity generation from some important conventional energy sources are discussed below: 1.1 Thermal Sources (Coal) Thermal energy is the energy released on combustion of fossil fuels (e.g. coal, natural gas). This energy is used to turn water to steam and rotates steam turbines which drives an electric generator. Figure 1.1.1: General Layout of Coal-fired Station Figure 1.1.1 shows layout of a typical coal-fired power station. Continuous source of coal is a prerequisite for thermal power generation. Coal is fed to the boiler through coal handling plant where impurities are removed and pure coal is pulverised to fine powder. This is done to increase efficiency of boiler as pulverised coal undergoes complete combustion. The mixture of pulverised coal and preheated air is burnt in combustion zone in boiler. [1] The ash produced as a result of combustion is removed to ash storage through coal handling plant. The heat energy released on combustion is utilised to convert water into steam at high temperature and pressure. Steel tubes run along the boiler walls in which water is converted to steam (figure 1.1.2). The flue gases exchange their heat in superheater, economiser and air preheater as they get exhausted to the atmosphere. High pressure superheated steam (through superheater) is expanded in series of turbines namely high pressure, intermediate pressure and low pressure turbines coupled to an alternator. As a result alternator rotates and electrical energy is generated which is stepped up with the help of a transformer for transmission. The expanded low pressure steam is exhausted in condenser to be condensed to water and reused.
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Conventional and non Conventional sources of energy
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Conventional and Non-Conventional Sources
of Energy
1. Electricity generation from Conventional Sources of Energy
Conventional energy sources are the sources which are abundantly used for power generation. The sources
mainly include coal, petroleum, natural gas, water and nuclear sources. This energy sources are exhaustible
except water which is renewable source of energy. Electricity generation from some important conventional
energy sources are discussed below:
1.1 Thermal Sources (Coal)
Thermal energy is the energy released on combustion of fossil fuels (e.g. coal, natural gas). This energy is used to turn
water to steam and rotates steam turbines which drives an electric generator.
Figure 1.1.1: General Layout of Coal-fired Station
Figure 1.1.1 shows layout of a typical coal-fired power station. Continuous source of coal is a prerequisite for thermal
power generation. Coal is fed to the boiler through coal handling plant where impurities are removed and pure coal is
pulverised to fine powder. This is done to increase efficiency of boiler as pulverised coal undergoes complete
combustion. The mixture of pulverised coal and preheated air is burnt in combustion zone in boiler. [1] The ash
produced as a result of combustion is removed to ash storage through coal handling plant. The heat energy released
on combustion is utilised to convert water into steam at high temperature and pressure. Steel tubes run along the
boiler walls in which water is converted to steam (figure 1.1.2). The flue gases exchange their heat in superheater,
economiser and air preheater as they get exhausted to the atmosphere. High pressure superheated steam (through
superheater) is expanded in series of turbines namely high pressure, intermediate pressure and low pressure turbines
coupled to an alternator. As a result alternator rotates and electrical energy is generated which is stepped up with the
help of a transformer for transmission. The expanded low pressure steam is exhausted in condenser to be condensed
to water and reused.
Figure 1.1.2: Schematic of Coal-Fired Thermal Power Plant
1.2 Nuclear Sources
Nuclear energy is a result of nuclear reaction viz. fusion and fission reactions. The nuclear fission reaction involves
breaking down heavy nucleus to stable lighter nuclei while fusion reaction combines lighter nuclei to heavy stable
nucleus towards Iron (Fe) (most stable element). The figure 1.2.1 shows the stability of various nuclei. Both type of
nuclear reactions are accompanied by mass deficit and is directly proportional to the amount of energy released. [1]
Figure 1.2.1: Binding Energy per Nucleon vs Mass Number Curve
Figure 1.2.2: Schematic Arrangement of Nuclear Power Plant [2]
Nuclear power plant uses the same technology as that of conventional steam power generation with nuclear reactor
for heat generation instead of coal furnace and boiler. [2] Figure 1.2.2 shows the schematic arrangement of nuclear
power plant. Most nuclear power stations use Uranium as fuel. When bombarded with neutrons, Uranium undergoes
fission reaction in 35 ways one of them is as follows:
Each of the neutrons produced in the reaction strikes with another Uranium nucleus, thus causing nine subsequent
reactions and so on to form a chain reaction as shown in figure 1.2.3. The tremendous amount of heat energy
Figure 1.2.3: Chain Reaction of Uranium-235
produced in fission of Uranium or other heavy elements in nuclear reactor is extracted by pumping fluid or molten
metal like liquid sodium or gas through the pile. The heated metal or gas is then allowed to exchange its heat to the
heat exchanger by circulation. [2] Atomic power plants usually employ a double folded heat removal scheme shown in
figure 1.2.4. First, heat from reactor(R) is transferred from the fission reaction by the coolant. In next stage, in heat
exchanger (H), coolant transfers its heat to water. This produces steam in heat exchanger. Steam passes through
turbine (T) connected mechanically with the generator. The turbine rotates due to expansion of high pressure steam
and electrical power is generated from generator coupled to the turbine. After losing its energy in the turbine, the
steam is converted into water in the condenser (C) which is again delivered to the heat exchanger. [1]
Figure 1.2.4: Heat circuit in an atomic power plant [1]
This video explains functions of different parts of nuclear power plant.
1.3 Hydel Sources
The energy of water utilised for hydro-power generation can be kinetic or potential energy. Kinetic energy of water is
its energy in motion and is a function of mass and velocity while potential energy is a function of difference in level of
water between two points called the head. The hydro energy that can be generated is dependent on the quantity of
water available, the rate at which it is available and the head available. [1] The power generated is directly proportional
to the head available as greater head implies greater pressure to drive turbines. [1]