Question

The efficiency of a thermal power plant improves with.
A. Increased quantity of coal burnt.
B. Large quantity of water used.
C. Lower load in the plant.
D. Use of high steam pressure.

Answer 1

Hint: Thermal power plant is the plant where electricity is generated and the power plant whose efficiency is better to have more power generation. Therefore, for solving the above problem we must know the factors which are responsible for improving efficiency.

Complete step by step answer:
A thermal power plant is a power station in which heat energy is converted to electric power. In most of the thermal power plants a steam-driven turbine converts heat to mechanical power as an intermediate to electric power. There is a boiler present in which coal is used then water is filled in it. After that coal is burnt then after getting a decent amount of heat the water starts to boil and further turns into steam and drives a steam turbine which drives an electric generator. Now the question comes what is efficiency? The efficiency of any machine tells about how much output we are getting out of input provided. The efficiency of the power plant mainly depends upon pressure and temperature of the steam entering the turbine and pressure in the condenser. The thermal efficiency increases with the increase in temperature and pressure of steam entering the turbine. Therefore, we can say that use of high steam pressure can improve efficiency as a thermal power plant.
$\therefore$ The correct option is D.

Note: Sometimes questions are directly formed from how much the efficiency of a particular thermal power plant is. The efficiency is always represented in percentage. The typical coal-based power plant operating at steam pressure as $170bar$ and ${570^o}C$ run at efficiency at \[35\% \] to $38\% $ .