1 J (joule) = 1 W s = 4.1868 cal

1 GJ (gigajoule) = 10 E9 J

1 TJ (terajoule) = 10 E12 J

1 PJ (petajoule) = 10 E15 J

1 kWh (kilowatt-hour) = 3,600,000 J

1 toe (tonne oil equivalent)

= 7.4 barrels of crude oil in primary energy

= 7.8 barrels in total final consumption

= 1270 m ³ of naturalgas

= 2.3 metric tonnes of coal

Mtoe (million tonne oil equivalent) = 41.868 PJ

POWER

Electric power is usually measured in watts (W), kilowatts (kW), megawatts (MW), and so forth. Power is energy transfer per unit of time. Power (e.g., in watts) may be measured at any point in time, whereas energy (e.g., in kilowatt-hours) has to be measured over a certain period, for example, a second, an hour, or a year.

1 kW = 1000 W

1 MW = 1,000,000

1 GW = 1000 MW

1 TW = 1,000,000 MW

UNIT ABBREVIATIONS

m = meter = 3.28 feet (ft)

s = second

h = hour

W = watt

hp = horsepower

J = joule

cal = calorie

toe = tonnes of oil equivalent

Hz = hertz (cycles per second)

10 E 12 = pico (p) = 1/1000,000,000,000

10 E 9 = nano (n) = 1/1,000,000,000

10 E 6 = micro ( ?) = 1/1000,000

10 E 3 = milli (m) = 1/1000

10 E 3 = kilo (k) = 1000 = thousands

10 E 6 = mega (M) = 1,000,000...