A comparison of amount of energy before a conversion with the amount of useful energy after a conversion?

Usually, the amount of useful energy after a conversion will be less than the original energy. In no case can it be more.

Usually, the amount of useful energy after a conversion will be less than the original energy. In no case can it be more.

Usually, the amount of useful energy after a conversion will be less than the original energy. In no case can it be more.

Usually, the amount of useful energy after a conversion will be less than the original energy. In no case can it be more.