If energy efficiency is improved, the cost of energy would decrease and more coal would be available less electricity would be used homes would cost significantly less energy star appliances would no longer be necessary

less energy would need to be generated.

Explanation:

What is efficiency?

Energy efficiency just means that you need less energy for the same consumption or demand.

In distribution and transportation of energy we lose some of the energy generated at the power plants, be it in the form of heat radiation because of the resistance of power cables or in the form of electromagnetic radiation, so if we improve efficiency, then less energy is lost in those two ways to power the same demand. Putting it simply, let's say your house demands 10kW, and the cable connecting you with the utility loses 1kW, then:

1kW+10kW = 11kW <- That needs to be generated

But if we improve that efficiency by 50% then the loses are cut by half, 1kW/2=0.5kW, so:

0.5kW+10kW = 10.5 kW <- 0.5 kW less that need to be generated. Multiply that by the number of homes in America for example and you have  tremendous power-saving potential

multiply 2kg by latent heat of vap