Bituminous coal has a heat of combustion of 31.4 MJ/kg. In the United States the average coal-burning utility producesan average of 2.2 kWh of electrical energy per kilogram of bituminous coal burned. What is the average overall efficiency of this production of electricity

The average overall efficiency of the production of electricity is 25.22%.

Given data:

The heat of combustion produced by the coal is, .

The average electric energy produced per kg is, .

The given problem is based on the concept of overall efficiency. In general, it is general defined as the ratio of the energy produced and the heat of combustion due to burning of source (coal).

Then,

Solving as,

Thus, we can conclude that the average overall efficiency of the production of electricity is 25.22%.

Learn more about the overall efficiency here:

link

Explanation:

The average overall efficiency is given by the following expression:

the displacement produced by the body.  

the amount of force subjected to the body.  

the angle between the direction of force and displacement