Question

1. Thermal power generation converts heat energy to electric power. Elucidate the working principle of a thermal power generation. (10 marks)

Answer 1

Thermal power plant work on the principle of converting one form of energy to another (i.e Thermal to Electrical energy).The initial step in energy production is the processing of raw material/fuel. There are various raw materials like coal, nuclear, steam or biomass. All the above-mentioned quantities contain carbon, which has stored potential energy. The fuel is processed to make it more convenient for heat generation (breaking coal clusters into fine particles with uniform surface area helps in uniform combustion). This is followed by heating of the processed fuel. This process of heating usually occurs in the boilers of the thermal power plant, where the processed raw materials are heated up to 450°C along with a pressure of 3000psi. The system efficiency increases gradually during high temperature and pressure conditions. In this step, there is a conversion of stored potential energy to heat energy. This process is followed by the generation of steam. The generated heat energy from the fuel is then used to heat purified water to generate steam at high very temperature (beyond the critical point of water-705°F) and pressure. Here the heat energy from the fuel is converter into the heat energy of the steam. Finally, this process is succeeded by generation of electricity, in this process the high pressurised steam is allowed to flow through the turbine which in turn rotates the shaft of the alternator which works on the principle of faraday's law generates an electromotive force. Here there is a conversion of heat energy of the steam into the electrical energy which in turn is transmitted to various load ends. Hence the whole process of energy conversion in a thermal power plant is elucidated.