Tonne of oil equivalent
The tonne of oil equivalent (toe) is a unit of energy defined as the amount of energy released by burning one tonne of crude oil. It is approximately 42 gigajoules or 11,630 kilowatt-hours, although as different crude oils have different calorific values, the exact value is defined by convention; several slightly different definitions exist. The toe is sometimes used for large amounts of energy.
Multiples of the toe are used, in particular the megatoe (Mtoe, one million toe) and the gigatoe (Gtoe, one billion toe). A smaller unit of kilogram of oil equivalent (kgoe) is also sometimes used denoting 1/1000 toe.
- 1 toe = 11.63 megawatt-hours (MWh)
- 1 toe = 41.868 gigajoules (GJ)
- 1 toe = 10 gigacalories (Gcal) – using the international steam table calorie (calIT) and not the thermochemical calorie (calth)
- 1 toe = 39,683,207.2 British thermal units (BTU)
- 1 toe = 1.42857143 tonnes of coal equivalent (tce)
Conversion into other units:
Some other sources and publications use divergent definitions of toe, for example:
- 1 barrel of oil equivalent (boe) contains approximately 0.136 toe (i.e. there are approximately 7.4 boe in a toe).
- 1 t diesel = 1.01 toe
- 1 m3 diesel = 0.98 toe
- 1 t petrol = 1.05 toe
- 1 m3 petrol = 0.86 toe
- 1 t biodiesel = 0.86 toe
- 1 m3 biodiesel = 0.78 toe
- 1 t bioethanol = 0.64 toe
- 1 m3 bioethanol = 0.51 toe
- 1 MWh = 0.086 toe  (therefore 1 toe = 11630.0 kWh) 
- At thermal power plants, 1 MWh is generated with 0.22 toe fuel or 0.39 MWh with 0.086 toe (39% thermal to electrical conversion efficiency)
Tonne of oil equivalent should be used carefully when converting electrical units. For instance, BP's 2007 report used a factor of 38% efficiency (the average efficiency of OECD thermal generating units in 2006), or roughly 16 GJ per toe, when converting kilowatt-hours to toe.
For multiples of the tonne of oil equivalent, it is more usual to speak of millions of tonnes of oil equivalent and kilotonnes of oil equivalent (ktoe).
|103||kilotonne of oil equivalent||ktoe|
|106||megatonne of oil equivalent||Mtoe|
- "IEA – Unit Converter". International Energy Agency. Retrieved 5 May 2015.
- American Physical Society
- Definition at 41.85 GJ
- Biofuels in the European Union progress report
- IEA Statistics
- The Society of Petroleum Engineers
- World Energy Council Archived 2008-05-29 at the Wayback Machine
- "BP Statistical Review of World Energy 2007" (XLS). Retrieved 2007-11-10.