Floyd's epic climb (clean or not) was around 450 or 470 watts, not 750 - still prodigious!

Energy is the amount of work you do to accomplish a specific task. If you bike from Ann Arbor, MI to Chelsea, MI at a certain average speed, you use a certain amount of energy measured in joules, watt-hours (watts times hours), or calories. If you bike from Ann Arbor to Chelsea and back all at the same speed, you use twice the amount of energy.

Power is the rate at which energy is expended. It's equal to force times velocity, and the tricky part is taht on a bike the force is proportional to the square of velocity, being dominated by aero drag, at speed. Power is equal to energy divided by the time over which it is expended. If you expend the same amount of energy in half the time, that's twice the power, and also needed twice the force.

If you bike from Ann Arbor round trip to Chelsea one week in two hours, you consume a certain amount of energy at a certain rate, aka power. If you bike the same route in one hour the next week, had half the time and hence twice the speed. Twice the speed means you applied four times the force. The power in the faster ride was 8 times the power in the slower ride.

It's really hard to go a lot faster than you do.

Based on what I've read, the iBike is still not a broadly useful power meter.