Description of Efficiency of a Plant
The percentage of the total energy content of a power plant's fuel that is converted into electricity is known as plant quality. Unless it is used for district heating, the remaining energy is normally lost to the atmosphere as heat. Divide the equivalent Btu content of a kWh of electricity (3,412 Btu) by the heat rate to express the efficiency of a generator or power plant as a percentage. If the heat rate is 10,500 Btu, for example, the efficiency is 33%. The efficiency is 45 percent if the heat rate is 7,500 Btu. Since 3,412 Btu/hr equals 1 kW, we can easily calculate a power plant's thermodynamic efficiency by dividing 3,412 by the heat rate.