{{short description|Unit of energy}}
The '''tonne of oil equivalent''' (abbreviated '''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 megawatt-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''' or '''koe''') is also sometimes used denoting 1/1000 toe.
A related concept is the physical quantity '''oil-equivalent mass''' (or '''mass of oil equivalent'''),<ref name="j177">{{cite book | last=Pohl | first=W.L. | title=Economic Geology: Principles and Practice | publisher=Wiley | year=2011 | isbn=978-1-4443-3663-4 | url=https://books.google.com/books?id=Y99FEAAAQBAJ&pg=PA523 | access-date=2025-03-05 | page=523}}</ref><ref name="g857">{{cite web | title=Glossary | website=AdEPorto | url=https://www.adeporto.eu/en/knowledge/glossary/ | access-date=2025-03-05}}</ref> expressed in the ordinary units of mass and its multiples: kilogram (kg), megagram (Mg) or tonne (t), etc.
==Definitions== The International Energy Agency defines one '' tonne of oil equivalent'' (toe) to be equal to:<ref name=IEA-unitconverter>{{cite web |url=https://www.iea.org/reports/unit-converter-and-glossary |title=Unit converter and glossary |date=December 2016 |publisher=International Energy Agency |access-date=22 December 2019}}</ref> *1 toe = 11.63 megawatt-hours (MWh) *1 toe = 41.868 gigajoules (GJ) *1 toe = 10 gigacalories (Gcal) – {{small|using the international steam table calorie (cal<sub>IT</sub>) and not the thermochemical calorie (cal<sub>th</sub>)<ref name="PAS-energy-units">[http://www.aps.org/policy/reports/popa-reports/energy/units.cfm American Physical Society]</ref>}} *1 toe = 39,683,207.2 British thermal units (BTU) *1 toe = 1.42857143 tonnes of coal equivalent (tce)
Conversion into other units: *1 toe = 7.33 barrels of oil equivalent (boe)<ref>{{cite web |url=http://www.opec.org/library/Annual%20Statistical%20Bulletin/interactive/current/FileZ/cfpage.htm |url-status=dead |archive-url=https://web.archive.org/web/20150509234952/http://www.opec.org/library/Annual%20Statistical%20Bulletin/interactive/current/FileZ/cfpage.htm |archive-date=2015-05-09 |title=OPEC Annual Statistical Bulletin 2014 - Conversion Factors}}</ref>
Some other sources and publications use divergent definitions of toe, for example: *1 toe = 10.7 gigacalories (Gcal) – {{small|using the thermochemical calorie<ref name="PAS-energy-units" />}} *1 toe = 41.85 gigajoules (GJ)<ref>[https://web.archive.org/web/20120206000109/http://www.cite-sciences.fr/lexique/definition1.php?idmot=145&rech_lettre=t&num_page=10&habillage=glp&lang=an&id_expo=13&id_habillage=24 Definition at 41.85 GJ]</ref> *1 toe = 44.769 gigajoules (GJ) – {{small|based on using thermochemical calorie (cal<sub>th</sub>)<ref name="PAS-energy-units" />}} *1 toe = 39,683,205.411 British thermal units (BTU){{citation needed|date=May 2015}}
==Conversion factors== *1 barrel of oil equivalent (boe) contains approximately 0.136 toe (i.e. there are approximately 7.33 boe in a toe).<ref>{{cite web |url=http://www.spe.org/industry/unit-conversion-factors.php |url-status=dead |archive-url=https://web.archive.org/web/20150202034008/http://www.spe.org/industry/unit-conversion-factors.php |archive-date=2015-02-02 |title=Unit Conversion Factors {{!}} Society of Petroleum Engineers}}</ref> *1 t diesel = 1.01 toe *1 m<sup>3</sup> diesel = 0.98 toe *1 t petrol = 1.05 toe *1 m<sup>3</sup> petrol = 0.86 toe *1 t biodiesel = 0.86 toe *1 m<sup>3</sup> biodiesel = 0.78 toe *1 t bioethanol = 0.64 toe *1 m<sup>3</sup> bioethanol = 0.51 toe<ref>[http://ec.europa.eu/energy/res/legislation/doc/biofuels/2006_05_05_consultation_en.pdf Biofuels in the European Union progress report<!-- Bot generated title -->]</ref> *1 MWh = 0.086 toe <ref>[http://www.iea.org/Textbase/stats/unit.asp IEA Statistics]</ref> (therefore 1 toe = 11630.0 kWh) <ref>[http://www.spe.org/industry/docs/UnitConversion.pdf The Society of Petroleum Engineers]</ref> *At thermal power plants, 1 MWh is generated with 0.22 toe fuel or 0.39 MWh with 0.086 toe<ref>[http://www.worldenergy.org/publications/survey_of_energy_resources_2007/625.asp World Energy Council<!-- Bot generated title -->] {{Webarchive|url=https://web.archive.org/web/20080529020947/http://www.worldenergy.org/publications/survey_of_energy_resources_2007/625.asp |date=2008-05-29 }}</ref> (39% thermal to electrical conversion efficiency)
Tonne of oil equivalent should be used carefully when converting electrical units. For instance, BP's 2022 report used a factor of 40% efficiency (the average efficiency of a standard thermal power plant in 2017), or roughly 16.8 GJ per toe, when converting kilowatt-hours to toe. BP's model is also based on the assumption that efficiency will increase linearly to 45% by 2050. <ref name ="bp2022">{{cite web |url=https://www.bp.com/content/dam/bp/business-sites/en/global/corporate/pdfs/energy-economics/statistical-review/bp-stats-review-2022-full-report.pdf | title=BP Statistical Review of World Energy 2022 |access-date=2023-02-22}}</ref>
==Derived units== 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). {|class="wikitable" style="text-align:center" |- ! Multiple !Name !Symbol |- |style="text-align:right"|10<sup>3</sup> || kilotonne of oil equivalent ||ktoe |- |style="text-align:right"|10<sup>6</sup> || megatonne of oil equivalent ||Mtoe |}
==See also== {{Portal|Energy}}
* {{annotated link|A Cubic Mile of Oil|''A Cubic Mile of Oil''}} * {{annotated link|Barrel of oil equivalent}} * {{annotated link|Conversion of units}} * {{annotated link|Energy density}} * {{annotated link|TNT equivalent}} a unit of energy almost exactly 0.1 tonnes of oil equivalent
==References== {{Reflist}}
== External links== *[http://www.iea.org/statistics/resources/unitconverter/ IEA's Unit Converter]
Category:Units of energy Category:Equivalent units Category:Petroleum economics