Introduction to Energy:
In this modern world, the dependence on electricity is so much that it has become a part of our life. The ever-increasing use of electric power for domestic commercial and industrial purposes is necessary to provide bulk electric power economically. This is achieved with the help of suitable power-producing units known as power plants or electric power generating stations.
A generating station essentially employs a prime mover coupled to an alternator for the production of electric power. The prime mover, (for example, steam turbine water turbine, etc.) converts energy from some other form into mechanical energy the alternator converts the mechanical energy of the prime mover into electrical energy. The electrical energy produced by the generating station is transmitted and inter distributed with the help of conductors to various consumers.
Types of Power Stations/Plants:
The generating stations are classified as under
1) Steam power station (Thermal Station)
2) Hydroelectric power station
3) Diesel power station
4) Nuclear power station
5) Gas turbine power station
A steam power station (Thermal Station):
A generating station that converts heat energy from coal combustion into electrical energy is known as a steam power station.
It works on the Rankine cycle. Steam is produced in the boiler by utilizing the heat of coal combustion. The steam is then expanded in a prime mover (for example steam turbine) and is condensed in a condenser to be fed into the boiler again.
The steam turbine drives the alternator which converts the mechanical energy of the turbine into electrical energy. This type of power station is suitable for coal and water is available in abundance and a large amount of electrical power is to be generated.
Hydroelectric power station:
The station which utilizes the potential energy of water at a high level of the generating of electrical energy is known as a hydroelectric power station.
Hydroelectric power stations are generally located in hilly areas where dams can be built conveniently and that virtual reservoir can be obtained. In a hydroelectric power station, water heat is created by constructing a dam across a river or lake.
From the dam water the hydraulic energy (for example product of heat and flow of water) into mechanical energy at the turbine shaft. The turbine drives the alternator which converts mechanical energy into electrical energy. Hydroelectric power stations are becoming very popular because the reserves of foils (for example coal and oil) are depleting day by day. They have the added importance for flood control storage of water for irrigation and water drinking purposes.
Diesel power station:
A generating station in which a diesel engine is used as the prime mover for the generation of electrical energy is known as a diesel power station.
In a diesel power station, the diesel engine is used as the prime mover. The diesel burns inside the engine and the products of the combustion act as the working fluid to produce mechanical energy. The diesel engine drives the alternator which converts mechanical energy into electrical energy.
As the generation cost is considerable due to the high price of diesel therefore such power stations are only used to produce small power. Although steam power stations and hydroelectric plants are invariably used to generate bulk power at a cheaper cost. Yet diesel power stations are finding favor in places where the power demand is less, sufficient quantity of coal and water is not available and the transportation facilities are inadequate.
These plants are also used as standby sets of continuity of supply to important points such as hospitals, radio stations, cinema houses, and telephone exchanges.
Nuclear power station:
A generating station in which nuclear energy is converted into electrical energy is known as a nuclear power station.
In a nuclear power station, heavy elements such as Uranium or Thorium are subjected to nuclear fission in a spatial known as a rotor. The heat energy thus released is utilized in raising steam at high temperatures and pressure. The steam runs the steam turbine which converts steam energy into mechanical energy. The turbine drives the alternator which converts mechanical energy into electrical energy.
The most important feature of a nuclear station is the huge amount of electrical energy that can be produced from a relatively small amount of nuclear fuel. As compared to other conventional types of power stations. It has been found that the complete fission of one kg of uranium can produce as much energy as can be produced by the burning of 4500 tons of high-grade coal.
Although the recovery of principal nuclear fuels (for example uranium and thorium) is difficult and expensive. Yet the total energy content of the estimated world reserves of these wells is considerably higher than those of conventional fuels coal and gas. At present, the energy crisis is gripping us and therefore nuclear energy can be successfully employed for producing low-cost electrical energy. On a large scale to meet the growing commercial and industrial demands.
Gas turbine power station: 
A generating station that employs a gas turbine as the prime mover for the generation of electrical energy is known as a gas turbine power station.
In a gas turbine power plant air is used as the working fluid. The air is compressed by the compressor and is led to the combustion chamber where heat is added to the air thus raising its temperature. Heat is added to the compressed air either by turbine fuel in the chamber or by the use of air heaters.
The hot and high-pressure air from the combustion chamber is then passed to the gas turbine where it expands and does the mechanical work. The gas turbine drives the alternator which converts mechanical energy into electrical energy. It may be mentioned here that the compressor gas turbine and the alternator are mounted on the same shaft or that a part of the mechanical power of the turbine can be utilized for hydroelectric stations. As starting plan for driving auxiliaries in power plants etc.