The electricity we use in our daily lives come to us after overcoming some certain steps. The main steps are generation, transmission, and distribution. The most important of them is generation. Power is generated at power plants. There are various types of power plants like thermal power plants( coal is used as fuel), hydel power plant(water force is used to rotate the turbine), nuclear power plants(nuclear energy is used), wind turbine plant, solar power plant.
The most economical power plant is thermal power plant. The fuel (coal) is also not very costly. In thermal power plant coal is used as the fuel to heat up the water and produce the steam, which at high pressure rotates the turbine, the steam is then turned back into water by condenser and again used for producing steam. This whole process can be represented by a line diagram.
1. At first coal is burnt and the boiler is heated up.
2. Then steam at high pressure is produced and again this steam is superheated.
3. This superheated steam is used to rotate the turbine.
4. After rotating the turbine the steam condenses and come to low pressure which again is heated and turned into steam.
5. The rotating turbine acts as the prime mover of the alternator.
The line diagram of thermal power plant explains this in a lot easier way.