Physiologists say that our brain produces as much bioelectronic energy as a light-bulb. But I assume that the power of different people's brains varies in a certain range. My idea is actually measuring individual brain potency in electronic Watts and monitoring its change through a day cycle.
I don't know yet if electronic brain potency correlates positively with intellectual abilities, but such measure would be less culture-dependent than IQ tests, plus it would be impossible to cheat.