Towards Green Energy

 Towards Green Energy

 

Ä ‘Energy is a stored ability or capacity of a body to do work.’ Hence, in order to carry out work, we need energy.

Ä The energy required to perform mechanical work, is called mechanical energy. It is of two types; namely, potential energy and kinetic energy.

Ä Energy can be converted from one form to another. The total energy in the universe always remain constant.

Ä Most of the electric power plants are based on the principle of electromagnetic induction invented by Michael Faraday. According to him, whenever magnetic field around a conductor changes, a potential difference is generated across the conductor.

Ä The magnetic field around a conductor can be changed in two ways. If a conductor is stationary and magnet is rotating, the field around conductor changes or if a magnet is stationary but the conductor is moving then also the field around the conductor will change. Thus in both the cases, a potential difference is produced across the conductor.

Ä The electric power generating machine based on this principle is called ‘electric generator’.

Ä The electric generator converts mechanical energy into electrical energy.

Ä in the thermal power stations, coal is burnt and heat energy is then converted to electrical energy. Here, chemical energy of coal is first converted into heat and then into kinetic energy of steam and ultimately to electrical energy.

Ä Thermal power plant has boiler, turbine, generator, condenser, etc.

Ä Due to thermal power plants CO2, SO2, NO2, carbon particles are added to air resulting in air pollution.

Ä In the nuclear power plant, steam turbine is used to rotate the generator. However here, the energy released by fusion of nuclei of atoms like Uranium or Plutonium is used to generate the steam of very high temperature and high pressure.

Ä In the nuclear power plant, the nuclear energy is first converted into thermal energy, then thermal energy is converted into kinetic energy of steam, then kinetic energy of steam is converted into kinetic energy of turbine and finally kinetic energy of turbine is converted into electrical energy.

Ä When a slow moving neutron is bombarded on uranium nucleus, the splitting of uranium nucleus takes place, Barium and Krypton nuclei are formed with release of three neutrons, with release of tremendous amount of energy, this process is called ‘nuclear fission’.

Ä The products after fission of nuclear fuel are also radioactive and emit harmful radiations.

Ä In the power generation plant based on natural gas, the turbine is run by a gas at very high temperature and pressure generated by combustion of a natural gas.

Ä In this plant, pressurised air is introduced into the combustion chamber using a compressor, Natural gas is burnt in the chamber at very high temperature and pressure generated in this chamber runs the turbines. The turbine then drives the generator to produce electricity.

Ä The efficiency of power plant based on natural gas is more than thermal power plant. Even the air pollution is greatly reduced.

Ä In Hydroelectric power plant, the potential energy in water stored in dam is converted into kinetic energy of water. This kinetic energy drives the turbines. The turbines drive the generator to produce electricity.

Ä Since no fuel is burnt in hydro-electric power generation, there is no pollution, but obstruction of water affects living world in the river.

Ä Wind energy can also be used to obtain electrical energy.

Ä The machine that converts the kinetic energy of wind into electrical energy is called wind-turbine.

Ä Wind energy is a clean source of energy.

Ä The electrical energy can also be generated by using solar energy. This can be done by two ways, solar photo-voltaic cells and Solar thermal power plant.

Ä In solar photovoltaic cells, the electricity is generated without using generator and without using principle of electro-magnetic induction. Photovoltaic cells convert the solar radiation energy directly into electrical energy.

Ä In the second method, the energy of solar radiations is converted into thermal energy first. Then the turbine-generator system is driven using that thermal energy to generate electricity.

Ä Solar energy is the most eco-friendly energy.