As we all knew that the energy can neither be created nor destroyed. Efficiency is basically the measure of the amount of an energy converted to another form. Basically, fuel efficiency can be defined as the efficiency of the process in which thermal energy given to the fuel converts the chemical potential energy of fuel to kinetic energy.
The efficiency of all the fuels varies with the device. In terms of the economy also, the efficiency of the fuel depends upon the energy efficiency of a particular device. The efficiency of fuels is measured in kilometers per liter in India, miles per gallon (mpg) in the U.S. and there are other measurement systems for different countries based on their standard units of use for the measurement of efficiency.
Coal: Coal is responsible for 41% of world’s electricity generation. The overall efficiency of a coal power plant is 32% to 42%.
For example, let us take an example of two fuels: Gasoline and diesel oil and see why it differs in efficiency and cost.
Diesel oil: We see that people choose diesel not gasoline since it saves money. Most of the diesel consumption is seen in big trucks but nowadays diesel is also used in other segment vehicles. Diesel is 33% more efficient than gasoline when it comes to fuel mileage. This means that if we get 40 miles to the gallon on gasoline, a diesel equivalent engine will give 53.2 miles per gallon. A Diesel engine offers more torque than gasoline engines, this torque allows greater acceleration and helps to increase the fuel economy.
Factors which determine fuel efficiency:
Environmental effects: This is the most primary reason why we choose the most efficient fuel. That is why we choose a diesel car as it uses less fuel per mile and it gives out less carbon dioxide. But diesel fuels are not totally pollution free. It releases some compounds which are carcinogenic and very harmful to the environment.
Engine performance: Engine performance decides the cost as well as the efficiency of the fuel. Diesel has a better engine performance, therefore, it is cheaper.
Noise: This is also one of the important criteria. Diesel does not produce smoke or dust but gives a roaring noise.