When coal is burned to produce electricity, the electrical energy produce is less than the potential energy of the coal. What does it means?
The chemical energy stored in coal may be worth say 100J The electrical energy produced may be only 30J Where has the 70J gone? Well, it will be lost mostly as heat to the surroundings: Heat in the turbines, heat in the wires and pipes, heat in the transformer etc Also sound energy, light energy and so on. So lots of the energy in coal is wasted and not all of that energy makes it to the end consumer in their home.
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