Power vs Energy

Power and energy are often confused, at least in the beginning.  Energy is the propensity to do work.  Infact the terms work and energy are often used interchangeably.  They ARE representative of each other in all respects EXCEPT for the propensity part. We would commonly say we "store" energy and "perform" work.  However, if we measured the work and the energy it took to perform it, we should get the same numbers. There is debate about this, but in a scientific discussion we would use "energy" most of the time.  It is more of a vernacular decision than a scientific one.

Power is the rate at which the work is performed.  So, moving a pile of rocks would require energy.  If we moved the rocks in the same conditions (level ground, same mass of rocks etc.)  the energy required would not change.  But, if we moved the rocks slowly the first time and quickly the next time, the latter would require more power...but the same amount of energy.

Power is the rate at which you expend energy.  Nothing more than that.

If you give me a task to do, the energy cannot be changed to perform that task, but the power required could be drastically different, based on the time allotted to accomplish the task.

If a construction crew moved 20 yards of dirt with a shovel, it takes the same energy as a bulldozer doing it.  the difference is, the bulldozer has more power, so it can do it faster.