The higher the voltage the less Ampere's are recquired to do the same amount of work. It all depends on the ciruit, but more volts does not at all mean that energy consumption has to be higher.

If I needed to do 200watts of work I could use 200amps@1 volt.
I can do the same amount of work with only 133amps if I use 1.5 volts.

Volts x amps =watts. So in the end im still using 200 watts both ways.