What is difference between 2000W and 1500W and how to find out how much powerelectricity each consumes?

To find the power will depend on the voltage the item uses. Assuming a 120 volt circuit divide the wattage by the voltage, this gives the amps used. 2000w / 120v = 16.67 amps. 1500w/ 120v = 12.5 amps used.