Question

we learnt that the total energy during a physical or chemical process is conserved. Why, then, do we hear so much about the energy crisis? If energy can neither be created nor destroyed, we should have no worries! We should be able to perform endless activities without thinking about energy resources!

Answer 1

According to law of conservation of energy,energy can neither be created nor destroyed. It can only be converted from one form to another.Thus,it is conserved.
But,the initial energy ,in the usable form,is dissipated into the surroundings into less usable form.Hence any source of energy we use to do work,is consumed and cannot be used again.That is the reason why we hear so much on energy crisis.
For example in a microwave oven, the electrical energy has been utilized (and dissipated) as heat. Similarly in television, it gets converted to light and sound energy, which cannot be reclaimed for usage again