ENERGY UNITS

selected from:

www.physics.uci.edu/~silverma/units.html and www.phy.syr.edu/courses/modules/ENERGY/ENERGY_POLICY/tables.html

Energy (the ability to do work) is measured in joules or calories
1 joule (J) is equal to the force of one newton acting through one meter
1 calorie (cal) of heat is the amount needed to raise 1 gram of water 1 degree centigrade
1 calorie   = 4.184 J
(But, the calories in food ratings are actually kilocalories, so 1 (kilo)calorie = 4184 J

Power is measured in watts
1 watt is the power from a current of 1 ampere flowing through 1 volt
Power = Current x Voltage
Energy = power x time
1 kilowatt is a thousand watts
1 kilowatt-hour is the energy of one kilowatt power flowing for one hour (E = P t)
1 kilowatt-hour (kwh) = 3.6 x 10⁶ J = 3.6 million joules
1 megawatt = a million watts

approximate energy content of fuels:
AA battery = 10³ J
candy bar = 10⁶ J
pound of coal = 1.6 x 10⁷ J
pound of uranium 235 = 3.7 x 10¹³ J

90 lbs coal = 1.1 day energy consumption per capita in U.S.

**for more rough values of power of various processes, and energy comparisons, see this great website