• Energy Efficiency- Percentage of the total energy input that does useful work and is not converted into low-quality, usually useless heat in an energy conversion system or process. See energy quality, net energy.
• Incandescent Light Bulb- One largely used devices that uses large amounts of energy, wastes 95% of its energy input of electricity
• Internal Combustion Engine- Another device that uses a lot of energy, wastes 75%-80% of the energy in its fuel
• Coal-Burning Power Plant- Device that uses a lot of energy, wastes 66% waste
• Net Energy- only energy that really counts
• Net Energy Efficiency- a measure of the useful energy we get from a resource after subtracting the energy used and wasted to