Power:

Power is the rate of doing the work. In System International Units (S. I.), the unit is Watt.

Watt = Joule per second

W = J s ^-1

In metric system of unit, Horse-power = 75 kgm/sec = 4500 kgm/min.

Energy:

Energy of body is its capacity to do work. Thus, the units of energy are the same as that of work (i.e. Joule). Energy possessed by a body may have different forms. It can be the energy in the form of Heat Energy, Electrical Energy or some other form.