# Electrical Conversions & Definitions

#### Electric Conversions

Electricity Conversion/Equivalency Charts & Definitions

Unit-of-Measure Equivalents

 Unit Equivalent Kilowatt (kW) 1,000 (One Thousand) Watts Megawatt (MW) 1,000,000 (One Million) Watts Gigawatt (GW) 1,000,000,000 (One Billion) Watts Terawatt (TW) 1,000,000,000,000 (One Trillion) Watts Gigawatt 1,000,000 (One Million) Kilowatts Thousand Gigawatts 1,000,000,000 (One Billion) Kilowatts Kilowatthours (kWh) 1,000 (One Thousand) Watthours Megawatthours (MWh) 1,000,000 (One Million) Watthours Gigawatthours (GWh) 1,000,000,000 One Billion) Watthours Terawatthours (TWh) 1,000,000,000,000 (One Trillion) Watthours Gigawatthours 1,000,000 (One Million) Kilowatthours Thousand Gigawatthours 1,000,000,000 (One Billion) Kilowatthours U.S. Dollar 1,000 (One Thousand) Mills U.S. Cent 10 (Ten) Mills Source: Energy Information Administration, Office of Coal, Nuclear, Electric and Alternate Fuels, Electric Power Division.

In order to convert from U.S. units to metric units using the conversion factors shown in the following table, multiply the number of U.S. units (e.g., 2 pounds) times the conversion factor shown (0.45359237) to obtain the equivalent number in metric units (2 pounds times 0.45359237 pounds/kilograms = 0.90718474 kilograms)

Metric Conversion

Mass

1 short ton (2,000 lb) = 0.9071847 metric tons (t)

1 pounds (lb) = 0.45359237a kilograms (kg)

Volume

1 barrel of oil (bbl) = 0.1589873 cubic meters (m3)

1 cubic foot (ft3) = 0.02831685 cubic meters (m3)

1 U.S. gallon (gal) = 3.785412 = liters (L)

Energy

1 British thermal unit (Btu) = 1,055.055 852 62ab joules (J)

aExact conversion.
bThe Btu used in this table is the International Table Btu adopted by the Fifth International Conference on Properties of Steam, London, 1956.
Notes: Spaces have been inserted after every third digit to the right of the decimal for ease of reading. Most metric units belong to the International System of Units (SI), and the liter and metric ton are acceptable for use with the SI units.
Sources: General Services Administration, Federal Standard 376B, Preferred Metric Units for General Use by the Federal Government (Washington, DC, January 27, 1993), pp. 9-11, 13, and 16. National Institute of Standards and Technology, Special Publications 330, 811, and 814. American National Standards Institute/Institute of Electrical and Electronic Engineers, SVIEEE Std 268-1992, pp. 28 and 29.

##### Useful Electricity Terms
• >A Btu or British Thermal Unit is a standard unit for measuring the quantity of heat energy equal to the quantity of heat required to raise the temperature of 1 pound (16 ounces) of water by 1 degree Fahrenheit.
• The Capacity Factor of a generating unit is the ratio of "the electrical energy produced by a generating unit for a given period of time" to "the electrical energy that could have been produced at continuous full-power operation during the same period."
• Efficiency is derived by dividing the heat content of 1 kilowatthour of electricity (3,412 Btu per kilowatthour) by the number of Btu contained in the input used to produce 1 kilowatthour.
• Energy is the capacity for doing work--as measured by the capability of doing work (potential energy) or the conversion of this capability to motion (kinetic energy). Energy has several forms, some of which can be converted into another form useful for work. Most of the world's convertible energy comes from fossil fuels that are burned to produce heat that is then used as a transfer medium to mechanical or other means in order accomplish tasks. Electrical energy is usually measured in watthours, while heat energy is usually measured in Btu.
• Heat Rate is a measure of generating station thermal efficiency--generally expressed in Btu per net kilowatthour. It is computed by dividing the total Btu content of fuel burned for electricity generation by the resulting net kilowatthour generation.
• An ohm is the unit of measurement of electrical resistance. It is the resistance of a circuit in which a potential difference of 1 volt produces a current of 1 ampere.

Source: U.S. Department of Energy / Office of Energy Information Administration