AP-ES: Energy Units

1 Joule (J)

The force exerted by a current of 1 amp per second flowing through a resistance of 1 ohm.

1 Watt (W)

1 joule (J) per second

1 Kilowatt-hour (kWh)

1 thousand (103) watts exerted for 1 hour

1 Megawatt (MW)

1 million (106) watts

1 Gigawatt (GW)

1 billion (109) watts

1 Petajoule (PJ)

1 quadrillion (1015) joules

1 PJ

947 billion Btu, or 0.278 billion kWh

1 British thermal unit (Btu)

Energy to heat 1 lb of water 1°F

1 Standard barrel (bbl) of oil

42 gal (160 liter) or 5.8 million Btu

1 Metric ton of standard coal

27.8 million Btu or 4.8 bbl oil