# Energy Units and Coversion Factors

Metric prefixes

 kilo (k) = 103 mega (M) = 106 giga (G) = 109 tera (T) = 1012 peta (P) = 1015 exa (E) = 1018

Volume

 1 m3 = 103 1 US gallon = 106 1 Imperial gallon = 109

Example:
1 TJ = 1,000 GJ = 1,000,000 MJ = 1,000,000,000 kJ = 1,000,000,000,000 J = 1012 J
1 J = 0.001 MJ = 0.000001 GJ = 0.000000001 TJ

Energy unit conversion

 Multiply by: GJ Toe MBtu MWh GJ 1 0.024 0.948 0.278 Toe 41.868 1 39.683 11.630 MBtu 1.055 0.025 1 0.293 MWh 3.600 0.086 3.412 1

Toe = tonnes oil equivalent

1 Mtoe = 41.9 PJ

Example: 1 MWh x 3.600 = 3.6 GJ

Heat of combustion (high heat values)

 1 l ethanol = 84,530 Btu / US gallon = 21.2 MJ / l 1 l biodiesel = 127,960 Btu / US gallon = 32.1 MJ / l

SOLAR THERMAL HEAT SYSTEMS

 million m² = 0.7 GWth

Used where solar thermal heat data have been converted from square metres (m²) into gigawatts thermal (GWth), by accepted convention.

Example:

1) These values can vary with fuel and temperature.
2) Around 1.5 litres of ethanol is required to equate to 1 litre of gasoline.
3) Heat values from U.S. Department of Energy Alternative Fuels Data Center.