View source for Primary energy

{{Short description|Energy form not subjected to any human conversion process}}
{{Other uses|PE (disambiguation){{!}}PE}}
{{Wikipedia:Latest world total primary energy consumption by type}}
{{Pie chart
| thumb   = right
| caption = World total primary energy supply of 162,494 [[Kilowatt hour#Watt hour multiples and billing units|TWh]] (or 13,792 [[tonne of oil equivalent|Mtoe]]) by region in 2017 (IEA, 2019)<ref name="IEA-Report-keyworld-2019">
{{cite web
 |title       = 2019 Key World Energy Statistics
 |date        = 2019
 |publisher   = IEA
 |url         = https://webstore.iea.org/download/direct/2831?fileName=Key_World_Energy_Statistics_2019.pdf
 }}</ref>
| other   = 
| label1  = OECD
| value1  = 38
| color1  = #66CCFF
| label2  = Middle East
| value2  = 5.4
| color2  = #FFFF57 
| label3  = Non-OECD Europe /Eurasia
| value3  = 8.0
| color3  = #009a39
| label4  = China
| value4  = 22
| color4  = #de2821
| label5  = Non-OECD Asia (w/o China)
| value5  = 13.4
| color5  = pink
| label6  = Non-OECD Americas
| value6  = 4.4
| color6  = #211873
| label7  = Africa
| value7  = 5.8
| color7  = #ef8e39
| label8  = Bunkers (marine/air)
| value8  = 3
| color8  = #313c42
}}
'''Primary energy''' ('''PE''') is the energy found in nature that has not been subjected to any human engineered conversion process. It encompasses energy contained in raw [[fuel]]s and other forms of energy, including waste, received as input to a [[system]]. Primary energy can be [[non-renewable resource|non-renewable]] or [[renewable energy|renewable]].

'''Total primary energy supply''' ('''TPES''') is the sum of production and imports, plus or minus stock changes, minus exports and international bunker storage.<ref>{{cite book|url=https://read.oecd-ilibrary.org/economics/oecd-factbook-2013_factbook-2013-en#page110|page=108|title=OECD Factbook 2013: Economic, Environmental and Social Statistics|year=2012|publisher=OECD Publishing|last=OECD|series=OECD Factbook |doi=10.1787/factbook-2013-en|isbn=9789264177062 |access-date=16 August 2021}}</ref>
The International Recommendations for Energy Statistics (IRES) prefers '''total energy supply (TES)''' to refer to this indicator.<ref>{{cite book |last1=Department of Economic and Social Affairs |title=International Recommendations for Energy Statistics |date=2018 |publisher=United Nations |location=New York|url=https://unstats.un.org/unsd/energystats/methodology/documents/IRES-web.pdf |page=105,137}}</ref> These expressions are often used to describe the total energy supply of a national territory.

'''Secondary energy''' is a carrier of energy, such as electricity. These are produced by conversion from a primary energy source.

Primary energy is used as a measure in [[Statistical study of energy data|energy statistics]] in the compilation of [[energy accounting|energy balances]],<ref>{{cite web |title=Primary energy |url=https://www.eia.gov/tools/glossary/index.php?id=P |website=Glossary |publisher=U.S. Energy Information Agency |access-date=18 August 2021 |location=Washington, DC}}</ref> as well as in the field of energetics. In energetics, a primary energy source (PES) refers to the energy forms required by the energy sector to generate the supply of [[energy carrier]]s used by human society.<ref name="GIAMPIETROMAYUMI2009">{{cite book |last1=Giampietro |first1=Mario |last2=Mayumi |first2=Kozo |title=The Biofuel Delusion: The Fallacy of Large Scale Agro-Biofuels Production |publisher=Earthscan, Taylor & Francis group |year=2009 |pages=336 |isbn=978-1-84407-681-9 }}</ref> Primary energy only counts raw energy and not usable energy and fails to account well for energy losses, particularly the large losses in thermal sources. It therefore generally grossly undercounts non thermal renewable energy sources .

==Examples of sources==
[[File:Global primary energy consumption by source 1900 - 2021.png|thumb|Global primary energy consumption by source]]
[[File:Global fossil fuel vs. low-carbon primary energy consumption, OWID.svg|thumb|Share of fossil fuels, nuclear and renewable energy in global primary energy consumption]]
Primary energy sources should not be confused with the [[energy system]] components (or conversion processes) through which they are converted into energy carriers.

{| class="wikitable"
|-
| colspan="3" valign="top" align="center" | '''Primary energy sources'''
| rowspan="11" valign="center" align="center" | ''converted<br/>by''
|''' Energy system component'''
| rowspan="11" valign="center" align="center" | ''to''
|'''[[Energy carrier]]s (main)'''
|-
| rowspan="4" valign="top" | '''''Non-renewable'''''<ref group="nb">At the scale of [[earth sciences]], all primary energy sources can be considered to be renewable. The non-renewable essence of resources (PES) is due to the scale of needs within human society. In certain situations, the use of resources by human society is performed at a much higher rate than the minimum rate at which it can be geophysically renewed. This is the rationale behind the differentiation between non-renewable primary energy sources (oil, coal, gas, uranium) and renewable primary energy sources (wind, solar, hydro).</ref>
| rowspan="2" valign="top" | '''''[[Fossil fuel|Fossil<br/>fuels]]'''''
| [[Petroleum|Oil]] (or crude oil)
| [[Oil refinery]]
| [[Fuel oil]]
|-
| [[Coal]] or [[natural gas]]
| [[Fossil fuel power station]]
| [[Enthalpy]], [[mechanical work]] or [[electricity]]
|-
| rowspan="2" | '''''Mineral<br/>fuels'''''
| [[Natural uranium]]<ref group="nb">Some [[nuclear fuel]]s, such as [[plutonium]] or [[depleted uranium]], are also used in nuclear fission power plants. However, they cannot be considered to be primary energy sources as they cannot be found in nature in any quantity. Indeed, there must be a consumption of natural uranium (primary energy source) in order to make these other nuclear fuels available.</ref>
| [[Nuclear power plant]] ([[thermonuclear fission]])
| Electricity
|-
|[[Thorium|Natural thorium]]
|[[Thorium-based nuclear power|Thorium breeder reactor]]
|Enthalpy or electricity
|-
| rowspan="6" colspan="2" valign="top" | '''''[[Renewable energy|Renewable]]'''''
| rowspan="2" valign="top" | [[Solar energy]]
| [[Photovoltaic]] power plant (''see also [[Solar power]]'')
| Electricity
|-
| [[Solar power tower]], [[solar furnace]] (''see also [[Solar thermal energy]]'')
| Enthalpy
|-
| [[Wind energy]]
| [[Wind farm]]  (''see also [[Wind power]]'')
| Mechanical work or electricity
|-
| Falling and flowing water, [[tidal energy]]<ref>[http://www.weltycenter.org/energy2.htm "Energy and the Natural Environment"] {{webarchive|url=https://web.archive.org/web/20081024051438/http://www.weltycenter.org/energy2.htm |date=2008-10-24 }} by David A. Dobson, Ph.D., Welty Environmental Center Feature Article, accessed July 9, 2009</ref>
| [[hydroelectricity|Hydropower station]], [[wave farm]], [[tidal power station]]
| Mechanical work or electricity
|-
| [[Biomass]] sources
| Biomass power plant
| Enthalpy or electricity
|-
| [[Geothermal energy]]
| [[Geothermal electricity#Power station types|Geothermal power station]]
| Enthalpy or electricity
|}

==Usable energy==
{{main|exergy}}
[[File:Different energy forms (PES).png|thumb|Primary energy sources are transformed by the energy sector to generate energy carriers.]]
Primary energy sources are transformed in [[energy conversion]] processes to more convenient forms of energy that can directly be used by society, such as [[electrical energy]], refined [[fuels]], or synthetic fuels such as [[hydrogen fuel]]. In the field of [[Energy|energetics]], these forms are called [[energy carrier]]s and correspond to the concept of "secondary energy" in energy statistics.

===Conversion to energy carriers (or secondary energy)===
Energy carriers are energy forms which have been transformed from primary energy sources. Electricity is one of the most common energy carriers, being transformed from various primary energy sources such as coal, oil, natural gas, and wind. Electricity is particularly useful since it has low [[entropy]] (is highly ordered) and so can be converted into other forms of energy very efficiently. [[District heating]] is another example of secondary energy.<ref>[https://www.energystar.gov/buildings/facility-owners-and-managers/existing-buildings/use-portfolio-manager/understand-metrics/difference   U.S. EPA Energy STAR] Retrieved 2017-11-03</ref>

According to the [[laws of thermodynamics]], primary energy sources cannot be produced. They must be available to society to enable the production of energy carriers.<ref name="GIAMPIETROMAYUMI2009" />

[[Thermal efficiency|Conversion efficiency]] varies. For thermal energy, electricity and mechanical energy production is limited by [[Carnot's theorem (thermodynamics)|Carnot's theorem]], and generates a lot of [[waste heat]]. Other non-thermal conversions can be more efficient. For example, while wind turbines do not capture all of the wind's energy, they have a high conversion efficiency and generate very little waste heat since wind energy is low entropy. In principle solar photovoltaic conversions could be very efficient, but current conversion can only be done well for narrow ranges of wavelength, whereas solar thermal is also subject to Carnot efficiency limits. Hydroelectric power is also very ordered, and converted very efficiently. The amount of usable energy is the [[exergy]] of a system.

===Site and source energy===
Site energy is the term used in North America for the amount of end-use energy of all forms consumed at a specified location. This can be a mix of primary energy (such as natural gas burned at the site) and secondary energy (such as electricity). Site energy is measured at the campus, building, or sub-building level and is the basis for energy charges on utility bills.<ref name="NRCan">{{cite web|title=Measuring energy: site energy vs. source energy in ENERGY STAR Portfolio Manager|date=28 March 2017 |url=http://www.nrcan.gc.ca/energy/efficiency/buildings/energy-benchmarking/update/getready/19453|publisher=[[Natural Resources Canada]]|access-date=November 8, 2017}}</ref>

Source energy, in contrast, is the term used in North America for the amount of primary energy consumed in order to provide a facility’s site energy. It is always greater than the site energy, as it includes all site energy and adds to it the energy lost during transmission, delivery, and conversion.<ref>{{Cite journal|last1=Torcellini|first1=Paul|last2=Pless|first2=Shanti|last3=Deru|first3=Michael|last4=Crawley|first4=Drury|date=June 2006|title=Zero energy buildings: a critical look at the definition|url=https://www.nrel.gov/docs/fy06osti/39833.pdf|journal=ACEEE Summer Study|publisher=National Renewable Energy Laboratory/U.S. Department of Energy}}</ref> While source or primary energy provides a more complete picture of energy consumption, it cannot be measured directly and must be calculated using conversion factors from site energy measurements.<ref name="NRCan" /> For electricity, a typical value is three units of source energy for one unit of site energy.<ref>{{cite web|title=Site Energy vs Source Energy|url=http://wbi.worldbank.org/energy/content/site-energy-vs-source-energy|publisher=The World Bank|access-date=November 8, 2017}}</ref> However, this can vary considerably depending on factors such as the primary energy source or fuel type, the type of power plant, and the transmission infrastructure. One full set of conversion factors is available as technical reference from [[Energy Star|Energy STAR]].<ref>{{Cite web|url=https://portfoliomanager.energystar.gov/pdf/reference/Source%20Energy.pdf|title=Technical Reference: Source Energy|access-date=2017-11-09}}</ref>

Either site or source energy can be an appropriate metric when comparing or analyzing energy use of different facilities. The U.S [[Energy Information Administration]], for example, uses primary (source) energy for its energy overviews<ref>{{Cite web|url=https://www.eia.gov/totalenergy/|title=Total Energy - U.S. Energy Information Administration (EIA)|website=www.eia.gov|access-date=2017-11-09}}</ref> but site energy for its Commercial Building Energy Consumption Survey<ref>{{Cite web|url=https://www.eia.gov/consumption/commercial/terminology.php|title=Commercial Buildings Energy Consumption Survey (CBECS) - U.S. Energy Information Administration (EIA)|website=www.eia.gov|language=en|access-date=2017-11-09}}</ref> and Residential Building Energy Consumption Survey.<ref>{{Cite web|url=https://www.eia.gov/consumption/residential/terminology.php|title=Residential Energy Consumption Survey (RECS) - U.S. Energy Information Administration (EIA)|website=www.eia.gov|language=en|access-date=2017-11-09}}</ref> The US [[United States Environmental Protection Agency|Environmental Protection Agency]]'s [[Energy Star|Energy STAR]] program recommends using source energy,<ref>{{Cite web|url=https://www.energystar.gov/buildings/facility-owners-and-managers/existing-buildings/use-portfolio-manager/understand-metrics/difference|title=The difference between source and site energy|website=www.energystar.gov|language=en|access-date=2017-11-09}}</ref> and the [[United States Department of Energy|US Department of Energy]] uses site energy in its definition of a [[Zero-energy building|zero net energy building]].<ref>{{Cite web|url=https://energy.gov/eere/buildings/articles/doe-releases-common-definition-zero-energy-buildings-campuses-and|title=DOE Releases Common Definition for Zero Energy Buildings, Campuses, and Communities|website=Energy.gov|access-date=2017-11-20}}</ref>

==Conversion factor conventions==
Where primary energy is used to describe [[fossil fuels]], the [[embodied energy]] of the fuel is available as thermal energy and around 70% is typically lost in conversion to electrical or mechanical energy. There are very much less significant conversion losses when hydroelectricity, wind and solar power produce electricity, but today's UN conventions on energy statistics counts the electricity made from hydroelectricity, wind and solar as the primary energy itself for these sources. One consequence of employing primary energy as an energy metric is that the contribution of hydro, wind and solar energy is under reported compared to [[fossil energy]] sources, and there is hence an international debate on how to count energy from non thermal renewables, with many estimates having them undercounted by a factor of about three.<ref>{{cite web|last1=Sauar|first1=Erik|title=IEA underreports contribution solar and wind by a factor of three compared to fossil fuels|url=http://energypost.eu/iea-underreports-contribution-solar-wind-factor-three-compared-fossil-fuels/|website=energypost.eu|date=31 August 2017 |publisher=Energy Post|access-date=22 April 2018}}</ref>

== See also ==

{{portal|Energy}}

* [[Energy industry]]
* [[Energy development]]
* [[Energy mix]]
* [[Energy system]]
* [[List of countries by total primary energy consumption and production]]

==Notes==
<references group="nb" />

== References ==

{{reflist|30em}}

== Further reading ==

* Kydes, Andy (Lead Author); Cutler J. Cleveland (Topic Editor). 2007. "Primary energy." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth June 1, 2006; Last revised August 14, 2007; Retrieved November 15, 2007.
* {{cite book
 | last1 = Øvergaard | first1 = Sara
 | title = Definition of primary and secondary energy
 | date = September 2008
 | publisher = [[Statistics Norway]]
 | location = Norway
 | url = http://unstats.un.org/unsd/envaccounting/londongroup/meeting13/LG13_12a.pdf
 | access-date = 2016-12-17
}}

==External links==
* [https://editors.eol.org/eoearth/wiki/Primary_energy The Encyclopedia of Earth: Primary energy]
* [https://web.archive.org/web/20120127193231/http://ourenergyfutures.org/page-cid-7.html#Primary_Energy_Sources Our Energy Futures glossary: Primary Energy Sources]
{{Footer energy}}
{{Authority control}}

[[Category:Energy]]
[[Category:Energetics]]
[[Category:Thermodynamics]]