View source for Earth:Coal

{{short description|Combustible sedimentary rock composed primarily of carbon}}
{{pp-move}}
{{pp-semi-indef}}
{{Infobox rock
|name=Coal
|type=Sedimentary
|image=Bituminous Coal.JPG
|image_caption=[[Earth:Bituminous coal|Bituminous coal]], the most common coal grade
|image_size=258px
|composition=[[Chemistry:Carbon|carbon]]
|composition_secondary={{plainlist|
* [[Chemistry:Hydrogen|hydrogen]]
* [[Chemistry:Sulfur|sulfur]]
* [[Chemistry:Oxygen|oxygen]]
* [[Chemistry:Nitrogen|nitrogen]]}}
}}

'''Coal''' is a combustible black or brownish-black [[Earth:Sedimentary rock|sedimentary rock]], formed as [[Earth:Stratum|rock strata]] called coal seams. Coal is mostly [[Chemistry:Carbon|carbon]] with variable amounts of other [[Chemistry:Chemical element|elements]], chiefly [[Chemistry:Hydrogen|hydrogen]], [[Chemistry:Sulfur|sulfur]], [[Chemistry:Oxygen|oxygen]], and [[Chemistry:Nitrogen|nitrogen]].<ref>{{cite web|last=Blander|first=M|title=Calculations of the Influence of Additives on Coal Combustion Deposits|url=http://www.anl.gov/PCS/acsfuel/preprint%20archive/Files/Volumes/Vol34-2.pdf|publisher=Argonne National Laboratory|access-date=17 December 2011|page=315|url-status=dead|archive-url=https://web.archive.org/web/20100528174436/http://www.anl.gov/PCS/acsfuel/preprint%20archive/Files/Volumes/Vol34-2.pdf|archive-date=28 May 2010}}</ref>
Coal is a type of fossil fuel, formed when dead plant matter decays into [[Earth:Peat|peat]] and is converted into coal by the heat and pressure of deep burial over millions of years.<ref name="EIA Coal Explained">{{cite web | url=https://www.eia.gov/energyexplained/index.cfm?page=coal_home | title=Coal Explained | publisher=US Energy Information Administration | work=Energy Explained | date=21 April 2017 | access-date=13 November 2017 | url-status=live | archive-url=https://web.archive.org/web/20171208115825/https://www.eia.gov/energyexplained/index.cfm?page=coal_home | archive-date=8 December 2017}}</ref> Vast deposits of coal originate in former [[Earth:Wetland|wetland]]s called [[Earth:Coal forest|coal forest]]s that covered much of the Earth's tropical land areas during the late [[Earth:Carboniferous|Carboniferous]] (Pennsylvanian) and [[Earth:Permian|Permian]] times.<ref name=ClealThomas2005>{{cite journal | last1 = Cleal | first1 = C. J. | last2 = Thomas | first2 = B. A. | year = 2005 | title = Palaeozoic tropical rainforests and their effect on global climates: is the past the key to the present? | journal = Geobiology | volume = 3 | issue = 1 | pages = 13–31 | doi = 10.1111/j.1472-4669.2005.00043.x | bibcode = 2005Gbio....3...13C | s2cid = 129219852 }}</ref><ref name="SahneyBentonFerry2010RainforestCollapse">{{cite journal |author=Sahney, S. |author2=Benton, M.J. |author3=Falcon-Lang, H.J. | year=2010 | title= Rainforest collapse triggered Pennsylvanian tetrapod diversification in Euramerica | journal=Geology | volume = 38 | pages = 1079–1082 | doi=10.1130/G31182.1 | issue=12 | bibcode=2010Geo....38.1079S}}</ref>

Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the [[History:Industrial Revolution|Industrial Revolution]]. With the invention of the [[Physics:Steam engine|steam engine]], coal consumption increased.{{Citation needed|date=February 2023}} In 2020, coal supplied about a quarter of the world's [[Physics:Primary energy|primary energy]] and over a third of its [[Engineering:Electricity generation|electricity]].<ref name=IEAstats2>{{cite web | url=https://www.iea.org/statistics/?country=WORLD&year=2016&category=Key%20indicators&indicator=ElecGenByFuel&mode=chart&categoryBrowse=false&dataTable=ELECTRICITYANDHEAT&showDataTable=false | title=Global energy data | publisher=[[Organization:International Energy Agency|International Energy Agency]] }}</ref> Some [[Chemistry:Iron|iron]] and steel-making and other industrial processes burn coal.

The extraction and use of coal causes premature death and illness.<ref name=Heal>{{cite web | url=https://www.env-health.org/wp-content/uploads/2018/12/HEAL-Lignite-Briefing-en_web.pdf | title=Lignite coal – health effects and recommendations from the health sector | publisher=Health and Environment Alliance |date=December 2018 }}</ref> The use of coal damages the environment, and it is the largest anthropogenic source of [[Chemistry:Carbon dioxide|carbon dioxide]] contributing to [[Earth:Climate change|climate change]]. Fourteen billion tonnes of carbon dioxide were emitted by burning coal in 2020,<ref name="cebf">{{Cite journal|title={{CO2}} emissions by fuel|url=https://ourworldindata.org/emissions-by-fuel|access-date=2021-01-22|journal=Our World in Data|date=11 May 2020|last1=Ritchie|first1=Hannah|last2=Roser|first2=Max}}</ref> which is 40% of the total fossil fuel emissions<ref name=phys2018/> and over 25% of total global [[Earth:Greenhouse gas emissions|greenhouse gas emissions]].<ref>{{Cite web|url=https://www.resilience.org/stories/2020-01-24/dethroning-king-coal-how-a-once-dominant-fuel-source-is-falling-rapidly-from-favour/|title=Dethroning King Coal – How a Once Dominant Fuel Source is Falling Rapidly from Favour|date=2020-01-24|website=Resilience|language=en-US|access-date=2020-02-08}}</ref> As part of worldwide energy transition, many countries have reduced or eliminated their use of coal power.<ref>{{Cite web|date=2020-08-03|title=Analysis: The global coal fleet shrank for first time on record in 2020|url=https://www.carbonbrief.org/analysis-the-global-coal-fleet-shrank-for-first-time-on-record-in-2020|access-date=2021-11-09|website=Carbon Brief|language=en}}</ref><ref>{{Cite web|last=Simon|first=Frédéric|date=2020-04-21|title=Sweden adds name to growing list of coal-free states in Europe|url=https://www.euractiv.com/section/energy/news/sweden-adds-name-to-growing-list-of-coal-free-states-in-europe/|access-date=2021-11-09|website=www.euractiv.com|language=en-GB}}</ref> The United Nations Secretary General asked governments to stop building new coal plants by 2020.<ref>{{cite news |title=Tax carbon, not people: UN chief issues climate plea from Pacific 'frontline' |url=https://www.theguardian.com/environment/2019/may/15/tax-carbon-not-people-un-chief-issues-climate-plea-from-pacific-frontline |work={{wipe|The Guardian}} |date=15 May 2019}}</ref> Global coal use was 8.3 billion tonnes in 2022.<ref name="record levels">{{cite web|author1=Anmar Frangoul
|title=IEA says coal use hit an all-time high last year — and global demand will persist near record levels|url=https://www.cnbc.com/2023/07/27/coal-consumption-hit-an-all-time-high-in-2022-iea-says.html#:~:text=According%20to%20the%20IEA%2C%20coal,a%20record%20high%20last%20year.&text=Coal%20consumption%20increased%20by%203.3,International%20Energy%20Agency%20said%20Thursday.|access-date=2023-09-10|website=CNBC|date=27 July 2023 |language=en}}</ref> Global coal demand is set to remain at record levels in 2023.<ref name=iea>{{Cite web|last=Frangoul|first=Frangoul|title=Global coal demand set to remain at record levels in 2023|url=https://www.iea.org/news/global-coal-demand-set-to-remain-at-record-levels-in-2023|access-date=2023-09-12|website=iea|language=en}}</ref> To meet the Paris Agreement target of keeping [[Earth:Global warming|global warming]] below {{convert|2|C-change|F-change|1}} coal use needs to halve from 2020 to 2030,<ref>{{Cite web|url=https://www.carbonbrief.org/analysis-why-coal-use-must-plummet-this-decade-to-keep-global-warming-below-1-5c|title=Analysis: Why coal use must plummet this decade to keep global warming below 1.5C|date=2020-02-06|website=Carbon Brief|language=en|access-date=2020-02-08}}</ref> and "phasing down" coal was agreed upon in the Glasgow Climate Pact.

The largest consumer and importer of coal in 2020 was China, which accounts for almost half the world's annual coal production, followed by India with about a tenth. Indonesia and Australia export the most, followed by Russia.<ref>{{Cite web|title=Exports – Coal Information: Overview – Analysis|url=https://www.iea.org/reports/coal-information-overview/exports|access-date=2022-01-20|website=IEA|language=en-GB}}</ref><ref name=":2">{{Cite journal |last1=Overland |first1=Indra |last2=Loginova |first2=Julia |date=2023-08-01 |title=The Russian coal industry in an uncertain world: Finally pivoting to Asia? |journal=Energy Research & Social Science |volume=102 |pages=103150 |doi=10.1016/j.erss.2023.103150 |issn=2214-6296|doi-access=free }}</ref>

==Etymology==
The word originally took the form ''col'' in [[Social:Old English|Old English]], from Proto-Germanic *''kula''(''n''), which in turn is hypothesized to come from the Proto-Indo-European root *''g''(''e'')''u-lo-'' "live coal".<ref name=etym>{{OEtymD|coal}}</ref> Germanic cognates include the [[Social:Old Frisian|Old Frisian]] ''kole'', [[Social:Middle Dutch|Middle Dutch]] ''cole'', [[Social:Dutch language|Dutch]] ''kool'', Old High German ''chol'', [[Social:German language|German]] ''Kohle'' and [[Social:Old Norse|Old Norse]] ''kol'', and the [[Social:Irish language|Irish]] word ''gual'' is also a cognate via the [[Social:Indo-European languages|Indo-European]] root.<ref name=etym/>

==Geology==

Coal is composed of macerals, minerals and water.<ref name="BGS">{{cite web | url=https://www.bgs.ac.uk/downloads/start.cfm?id=1404 | title=Coal  | publisher=British Geological Survey | date=March 2010}}</ref> Fossils and [[Earth:Amber|amber]] may be found in coal.<ref>Poinar GO, Poinar R. (1995) ''The quest for life in amber''. Basic Books, {{ISBN|0-201-48928-7}}, p. 133</ref>
===Formation===
[[File:Struktura chemiczna węgla kamiennego.svg| thumb|Example chemical structure of coal]]

The conversion of dead vegetation into coal is called coalification. At various times in the geologic past, the Earth had dense forests<ref>{{cite web|title=How Coal Is Formed |url=http://www.fe.doe.gov/education/energylessons/coal/gen_howformed.html|url-status=live|archive-url=https://web.archive.org/web/20170118113211/http://www.fe.doe.gov/education/energylessons/coal/gen_howformed.html|archive-date=18 January 2017}}</ref> in low-lying wetland areas. In these wetlands, the process of coalification began when dead plant matter was protected from biodegradation and oxidation, usually by mud or acidic water, and was converted into [[Earth:Peat|peat]]. This trapped the carbon in immense peat bogs that were eventually deeply buried by sediments. Then, over millions of years, the heat and pressure of deep burial caused the loss of water, methane and carbon dioxide and increased the proportion of carbon.<ref name="BGS"/> The grade of coal produced depended on the maximum pressure and temperature reached, with [[Chemistry:Lignite|lignite]] (also called "brown coal") produced under relatively mild conditions, and sub-bituminous coal, [[Earth:Bituminous coal|bituminous coal]], or [[Chemistry:Anthracite|anthracite coal]] (also called "hard coal" or "black coal") produced in turn with increasing temperature and pressure.<ref name="EIA Coal Explained" /><ref>{{Cite book| url = https://books.google.com/books?id=_29tNNeQKeMC&pg=PA18| title = Paleobotany: The Biology and Evolution of Fossil Plants| isbn = 978-0-12-373972-8| author1 = Taylor, Thomas N| author2 = Taylor, Edith L| author3 = Krings, Michael| year = 2009| publisher = Academic Press| url-status = live| archive-url = https://web.archive.org/web/20160516231216/https://books.google.com/books?id=_29tNNeQKeMC&pg=PA18| archive-date = 16 May 2016}}</ref>

Of the factors involved in coalification, temperature is much more important than either pressure or time of burial.<ref>{{cite web |title=Heat, time, pressure, and coalification |url=http://www.uky.edu/KGS/coal/coal-heat-time-pressure.php |website=Kentucky Geological Survey |publisher=University of Kentucky |access-date=28 November 2020}}</ref> Subbituminous coal can form at temperatures as low as {{ convert|35 to 80|C||sp=us}} while anthracite requires a temperature of at least {{convert|180 to 245|C||sp=us}}.<ref>{{cite web |title=Burial temperatures from coal |url=http://www.uky.edu/KGS/coal/coal-burial-temperature.php |website=Kentucky Geological Survey |publisher=University of Kentucky |access-date=28 November 2020}}</ref>

Although coal is known from most geologic periods, 90% of all coal beds were deposited in the [[Earth:Carboniferous|Carboniferous]] and [[Earth:Permian|Permian]] periods, which represent just 2% of the Earth's geologic history.<ref>{{cite book |last1=McGhee |first1=George R. |title=Carboniferous Giants and Mass Extinction: The Late Paleozoic Ice Age World |date=2018 |publisher=Columbia University Press |location=New York |isbn=9780231180979 |pages=98}}</ref> Paradoxically, this was during the [[Earth:Late Paleozoic icehouse|Late Paleozoic icehouse]], a time of global [[Earth:Ice age|glaciation]]. However, the drop in global sea level accompanying the glaciation exposed [[Earth:Continental shelf|continental shelves]] that had previously been submerged, and to these were added wide river deltas produced by increased [[Earth:Erosion|erosion]] due to the drop in [[Earth:Base level|base level]]. These widespread areas of wetlands provided ideal conditions for coal formation.{{sfn|McGhee|2018|pp=88-92}} The rapid formation of coal ended with the [[Earth:Permian–Triassic extinction event#Coal Gap|coal gap]] in the [[Earth:Permian–Triassic extinction event|Permian–Triassic extinction event]], where coal is rare.<ref name="Retallack1996">{{cite journal| last1=Retallack |first1=G. J.|last2= Veevers|first2=J. J.|last3= Morante|first3= R.|title=Global coal gap between Permian–Triassic extinctions and middle Triassic recovery of peat forming plants|journal=GSA Bulletin|volume=108|issue=2|pages=195–207|year=1996|doi = 10.1130/0016-7606(1996)108<0195:GCGBPT>2.3.CO;2|bibcode=1996GSAB..108..195R}}</ref>

Favorable geography alone does not explain the extensive Carboniferous coal beds.{{sfn|McGhee|2018|p=99}} Other factors contributing to rapid coal deposition were high [[Chemistry:Oxygen|oxygen]] levels, above 30%, that promoted intense [[Biology:Wildfire|wildfire]]s and formation of [[Chemistry:Charcoal|charcoal]] that was all but indigestible by decomposing organisms; high [[Chemistry:Carbon dioxide|carbon dioxide]] levels that promoted plant growth; and the nature of Carboniferous forests, which included [[Biology:Lycophyte|lycophyte]] trees whose determinate growth meant that carbon was not tied up in heartwood of living trees for long periods.{{sfn|McGhee|2018|pp=98-102}}

One theory suggested that about 360 million years ago, some plants evolved the ability to produce [[Biology:Lignin|lignin]], a complex polymer that made their [[Chemistry:Cellulose|cellulose]] stems much harder and more woody. The ability to produce lignin led to the evolution of the first trees. But bacteria and fungi did not immediately evolve the ability to decompose lignin, so the wood did not fully decay but became buried under sediment, eventually turning into coal. About 300 million years ago, mushrooms and other fungi developed this ability, ending the main coal-formation period of earth's history.<ref>{{cite book |title=Unsettled: What Climate Science Tells Us, What It Doesn't, and Why It Matters |first=Steven E. |last=Koonin |location=Dallas |publisher=BenBella Books |date=2021 |isbn=9781953295248 |page=44}}</ref><ref>{{cite journal |last1=Floudas |first1=Dimitrios |last2=Binder |first2=Manfred |last3=Riley |first3=Robert |last4=Barry |first4=Kerrie |last5=Blanchette |first5=Robert A. |last6=Henrissat |first6=Bernard |last7=Martínez |first7=Angel T. |last8=Otillar |first8=Robert |last9=Spatafora |first9=Joseph W. |last10=Yadav |first10=Jagjit S. |last11=Aerts |first11=Andrea |last12=Benoit |first12=Isabelle |last13=Boyd |first13=Alex |last14=Carlson |first14=Alexis |last15=Copeland |first15=Alex |last16=Coutinho |first16=Pedro M. |last17=de Vries |first17=Ronald P. |last18=Ferreira |first18=Patricia |last19=Findley |first19=Keisha |last20=Foster |first20=Brian |last21=Gaskell |first21=Jill |last22=Glotzer |first22=Dylan |last23=Górecki |first23=Paweł |last24=Heitman |first24=Joseph |last25=Hesse |first25=Cedar |last26=Hori |first26=Chiaki |last27=Igarashi |first27=Kiyohiko |last28=Jurgens |first28=Joel A. |last29=Kallen |first29=Nathan |last30=Kersten |first30=Phil |last31=Kohler |first31=Annegret |last32=Kües |first32=Ursula |last33=Kumar |first33=T. K. Arun |last34=Kuo |first34=Alan |last35=LaButti |first35=Kurt |last36=Larrondo |first36=Luis F. |last37=Lindquist |first37=Erika |last38=Ling |first38=Albee |last39=Lombard |first39=Vincent |last40=Lucas |first40=Susan |last41=Lundell |first41=Taina |last42=Martin |first42=Rachael |last43=McLaughlin |first43=David J. |last44=Morgenstern |first44=Ingo |last45=Morin |first45=Emanuelle |last46=Murat |first46=Claude |last47=Nagy |first47=Laszlo G. |last48=Nolan |first48=Matt |last49=Ohm |first49=Robin A. |last50=Patyshakuliyeva |first50=Aleksandrina |last51=Rokas |first51=Antonis |last52=Ruiz-Dueñas |first52=Francisco J. |last53=Sabat |first53=Grzegorz |last54=Salamov |first54=Asaf |last55=Samejima |first55=Masahiro |last56=Schmutz |first56=Jeremy |last57=Slot |first57=Jason C. |last58=St. John |first58=Franz |last59=Stenlid |first59=Jan |last60=Sun |first60=Hui |last61=Sun |first61=Sheng |last62=Syed |first62=Khajamohiddin |last63=Tsang |first63=Adrian |last64=Wiebenga |first64=Ad |last65=Young |first65=Darcy |last66=Pisabarro |first66=Antonio |last67=Eastwood |first67=Daniel C. |last68=Martin |first68=Francis |last69=Cullen |first69=Dan |last70=Grigoriev |first70=Igor V. |last71=Hibbett |first71=David S. |title=The Paleozoic Origin of Enzymatic Lignin Decomposition Reconstructed from 31 Fungal Genomes |journal=Science |date=29 June 2012 |volume=336 |issue=6089 |pages=1715–1719 |doi=10.1126/science.1221748|pmid=22745431 |bibcode=2012Sci...336.1715F |hdl=10261/60626 |s2cid=37121590 |hdl-access=free }}</ref><ref>{{Cite web | url=https://www.scientificamerican.com/article/mushroom-evolution-breaks-down-lignin-slows-coal-formation |title = White Rot Fungi Slowed Coal Formation|website = Scientific American}}</ref> Although some authors pointed at some evidence of lignin degradation during the Carboniferous, and suggested that climatic and tectonic factors were a more plausible explanation,<ref>{{Cite journal|last1=Nelsen|first1=Matthew P.|last2=DiMichele|first2=William A.|last3=Peters|first3=Shanan E.|last4=Boyce|first4=C. Kevin|date=2016-01-19|title=Delayed fungal evolution did not cause the Paleozoic peak in coal production|journal=Proceedings of the National Academy of Sciences|language=en|volume=113|issue=9|pages=2442–2447|doi=10.1073/pnas.1517943113|pmid=26787881|pmc=4780611|bibcode=2016PNAS..113.2442N|issn=0027-8424|doi-access=free}}</ref> reconstruction of ancestral enzymes by phylogenetic analysis corroborated a hypothesis that lignin degrading enzymes appeared in fungi approximately 200 MYa.<ref>Ayuso-Fernandez I, Ruiz-Duenas FJ, Martinez AT: Evolutionary convergence in lignin-degrading enzymes. Proc Natl Acad Sci USA 2018, 115:6428-6433.</ref>

One likely tectonic factor was the [[Earth:Central Pangean Mountains|Central Pangean Mountains]], an enormous range running along the equator that reached its greatest elevation near this time. Climate modeling suggests that the Central Pangean Mountains contributed to the deposition of vast quantities of coal in the late Carboniferous. The mountains created an area of year-round heavy precipitation, with no dry season typical of a [[Earth:Monsoon|monsoon]] climate. This is necessary for the preservation of peat in coal swamps.<ref>{{cite journal |last1=Otto-Bliesner |first1=Bette L. |title=Tropical mountains and coal formation: A climate model study of the Westphalian (306 MA) |journal=Geophysical Research Letters |date=15 September 1993 |volume=20 |issue=18 |pages=1947–1950 |doi=10.1029/93GL02235|bibcode=1993GeoRL..20.1947O }}</ref>

Coal is known from [[Earth:Precambrian|Precambrian]] strata, which predate land plants. This coal is presumed to have originated from residues of algae.<ref name="Tyler1957">{{Cite journal | doi = 10.1130/0016-7606(1957)68[1293:ACFPUH]2.0.CO;2 | bibcode = 1957GSAB...68.1293T | last1 = Tyler | first1 = S.A. | last2 = Barghoorn | first2 = E.S. | last3 = Barrett | first3 = L.P. | title = Anthracitic Coal from Precambrian Upper Huronian Black Shale of the Iron River District, Northern Michigan | journal = Geological Society of America Bulletin | volume = 68 | issue = 10 | page = 1293 | year = 1957 | issn = 0016-7606 }}</ref><ref name="Mancuso1981">{{Cite journal | doi = 10.2113/gsecongeo.76.4.951 | last1 = Mancuso | first1 = J.J. | last2 = Seavoy | first2 = R.E. | title = Precambrian coal or anthraxolite; a source for graphite in high-grade schists and gneisses | journal = Economic Geology | volume = 76 | issue = 4 | pages = 951–54 | year = 1981 | bibcode = 1981EcGeo..76..951M }}</ref>

Sometimes coal seams (also known as coal beds) are interbedded with other sediments in a cyclothem. Cyclothems are thought to have their origin in glacial cycles that produced fluctuations in [[Sea level|sea level]], which alternately exposed and then flooded large areas of continental shelf.<ref>Stanley, Steven M. ''Earth System History''. New York: W.H. Freeman and Company, 1999. {{ISBN|0-7167-2882-6}}  (p. 426)</ref>

====Chemistry of coalification====
The woody tissue of plants is composed mainly of cellulose, hemicellulose, and lignin. Modern peat is mostly lignin, with a content of cellulose and hemicellulose ranging from 5% to 40%. Various other organic compounds, such as waxes and nitrogen- and sulfur-containing compounds, are also present.<ref>{{cite book |last1=Andriesse |first1=J. P. |title=Nature and Management of Tropical Peat Soils |date=1988 |publisher=Food and Agriculture Organization of the United Nations |location=Rome |isbn=92-5-102657-2 |chapter=The Main Characteristics of Tropical Peats}}</ref> Lignin has a weight composition of about 54% carbon, 6% hydrogen, and 30% oxygen, while cellulose has a weight composition of about 44% carbon, 6% hydrogen, and 49% oxygen. Bituminous coal has a composition of about 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on a weight basis.<ref name=Perry>{{cite book |editor1-last=Robert Perry |editor2-last=Cecil Chilton |chapter=Chapter 9: Heat Generation, Transport, and Storage|first=William|last=Reid|title=Chemical Engineers' Handbook |date=1973 |edition=5}}</ref> This implies that chemical processes during coalification must remove most of the oxygen and much of the hydrogen, leaving carbon, a process called ''carbonization''.<ref>{{cite journal |last1=Ulbrich |first1=Markus |last2=Preßl |first2=Dieter |last3=Fendt |first3=Sebastian |last4=Gaderer |first4=Matthias |last5=Spliethoff |first5=Hartmut |title=Impact of HTC reaction conditions on the hydrochar properties and {{CO2}} gasification properties of spent grains |journal=Fuel Processing Technology |date=December 2017 |volume=167 |pages=663–669 |doi=10.1016/j.fuproc.2017.08.010}}</ref>

Carbonization proceeds primarily by [[Chemistry:Dehydration reaction|dehydration]], [[Chemistry:Decarboxylation|decarboxylation]], and demethanation. Dehydration removes water molecules from the maturing coal via reactions such as<ref name="hatcher-etal-1992">{{cite journal |last1=Hatcher |first1=Patrick G. |last2=Faulon |first2=Jean Loup |last3=Wenzel |first3=Kurt A. |last4=Cody |first4=George D. |title=A structural model for lignin-derived vitrinite from high-volatile bituminous coal (coalified wood) |journal=Energy & Fuels |date=November 1992 |volume=6 |issue=6 |pages=813–820 |doi=10.1021/ef00036a018}}</ref>

:2 R–OH → R–O–R + H<sub>2</sub>O
:2 R-CH2-O-CH2-R → R-CH=CH-R + H<sub>2</sub>O

Decarboxylation removes carbon dioxide from the maturing coal and proceeds by reaction such as<ref name="hatcher-etal-1992"/>

:RCOOH  →  RH  +  CO<sub>2</sub>

while demethanation proceeds by reaction such as

:2 R-CH<sub>3</sub> → R-CH<sub>2</sub>-R + CH<sub>4</sub>
:R-CH<sub>2</sub>-CH<sub>2</sub>-CH<sub>2</sub>-R → R-CH=CH-R + CH<sub>4</sub>

In each of these formulas, R represents the remainder of a cellulose or lignin molecule to which the reacting groups are attached.

Dehydration and decarboxylation take place early in coalification, while demethanation begins only after the coal has already reached bituminous rank.<ref>{{cite web |title=Coal Types, Formation and Methods of Mining |url=http://epcamr.org/home/content/reference-materials/coal-types-formation-and-methods-of-mining/ |publisher=Eastern Pennsylvania Coalition for Abandoned Mine Reclamation |access-date=29 November 2020}}</ref> The effect of decarboxylation is to reduce the percentage of oxygen, while demethanation reduces the percentage of hydrogen. Dehydration does both, and (together with demethanation) reduces the saturation of the carbon backbone (increasing the number of double bonds between carbon).

As carbonization proceeds, [[Chemistry:Aliphatic compound|aliphatic compound]]s (carbon compounds characterized by chains of carbon atoms) are replaced by [[Chemistry:Aromatic compound|aromatic compound]]s (carbon compounds characterized by rings of carbon atoms) and aromatic rings begin to fuse into polyaromatic compounds (linked rings of carbon atoms).<ref>{{cite journal |last1=Ibarra |first1=JoséV. |last2=Muñoz |first2=Edgar |last3=Moliner |first3=Rafael |title=FTIR study of the evolution of coal structure during the coalification process |journal=Organic Geochemistry |date=June 1996 |volume=24 |issue=6–7 |pages=725–735 |doi=10.1016/0146-6380(96)00063-0|bibcode=1996OrGeo..24..725I }}</ref> The structure increasingly resembles [[Physics:Graphene|graphene]], the structural element of graphite.

Chemical changes are accompanied by physical changes, such as decrease in average pore size.<ref>{{cite journal |last1=Li |first1=Yong |last2=Zhang |first2=Cheng |last3=Tang |first3=Dazhen |last4=Gan |first4=Quan |last5=Niu |first5=Xinlei |last6=Wang |first6=Kai |last7=Shen |first7=Ruiyang |title=Coal pore size distributions controlled by the coalification process: An experimental study of coals from the Junggar, Ordos and Qinshui basins in China |journal=Fuel |date=October 2017 |volume=206 |pages=352–363 |doi=10.1016/j.fuel.2017.06.028}}</ref> The macerals (organic particles) of lignite are composed of ''huminite'', which is earthy in appearance. As the coal matures to sub-bituminous coal, huminite begins to be replaced by vitreous (shiny) ''vitrinite''.<ref>{{cite web |title=Sub-Bituminous Coal |url=http://www.uky.edu/KGS/coal/coal-sub.php |website=Kentucky Geological Survey |publisher=University of Kentucky |access-date=29 November 2020}}</ref> Maturation of bituminous coal is characterized by ''bitumenization'', in which part of the coal is converted to [[Chemistry:Bitumen|bitumen]], a hydrocarbon-rich gel.<ref>{{cite web |title=Bituminous Coal |url=http://www.uky.edu/KGS/coal/coal-bituminous.php |website=Kentucky Geological Survey |publisher=University of Kentucky |access-date=29 November 2020}}</ref> Maturation to anthracite is characterized by ''debitumenization'' (from demethanation) and the increasing tendency of the anthracite to break with a [[Earth:Conchoidal fracture|conchoidal fracture]], similar to the way thick glass breaks.<ref>{{cite web |title=Anthracitic Coal |url=http://www.uky.edu/KGS/coal/coal-anthracite.php |website=Kentucky Geological Survey |publisher=University of Kentucky |access-date=29 November 2020}}</ref>

{{anchor|Ranks}}

===Types===
[[File:Sydney Mines Point Aconi Seam 038.JPG|thumb|Coastal exposure of the Point Aconi Seam in Nova Scotia]]
[[File:Coal Rank USGS.png|thumb|upright=1.35|Coal ranking system used by the United States Geological Survey]]

As geological processes apply [[Physics:Pressure|pressure]] to dead [[Chemistry:Biotic material|biotic material]] over time, under suitable conditions, its metamorphic grade or rank increases successively into:
* [[Earth:Peat|Peat]], a precursor of coal
* [[Chemistry:Lignite|Lignite]], or brown coal, the lowest rank of coal, most harmful to health when burned,<ref name=Heal/> used almost exclusively as fuel for electric power generation
** [[Earth:Jet (lignite)|Jet]], a compact form of lignite, sometimes polished; used as an ornamental stone since the Upper Palaeolithic
* Sub-bituminous coal, whose properties range between those of lignite and those of bituminous coal, is used primarily as fuel for steam-electric power generation.
* [[Earth:Bituminous coal|Bituminous coal]], a dense sedimentary rock, usually black, but sometimes dark brown, often with well-defined bands of bright and dull material. It is used primarily as fuel in steam-electric power generation and to make [[Chemistry:Coke (fuel)|coke]]. Known as steam coal in the UK, and historically used to raise steam in steam locomotives and ships 
* [[Chemistry:Anthracite|Anthracite coal]], the highest rank of coal, is a harder, glossy black coal used primarily for residential and commercial space heating.
* [[Chemistry:Graphite|Graphite]] is difficult to ignite and not commonly used as fuel; it is most used in pencils, or powdered for [[Physics:Lubrication|lubrication]].
* Cannel coal (sometimes called "candle coal") is a variety of fine-grained, high-rank coal with significant hydrogen content, which consists primarily of [[Earth:Liptinite|liptinite]].

There are several international standards for coal.<ref>{{cite web |title=Standards catalogue 73.040 – Coals |url=https://www.iso.org/ics/73.040/x/ |publisher=ISO}}</ref> The classification of coal is generally based on the content of volatiles. However the most important distinction is between thermal coal (also known as steam coal), which is burnt to generate electricity via steam; and metallurgical coal (also known as coking coal), which is burnt at high temperature to make steel.

Hilt's law is a geological observation that (within a small area) the deeper the coal is found, the higher its rank (or grade). It applies if the thermal gradient is entirely vertical; however, [[Earth:Metamorphism|metamorphism]] may cause lateral changes of rank, irrespective of depth. For example, some of the coal seams of the Madrid, New Mexico coal field were partially converted to anthracite by contact metamorphism from an igneous [[Earth:Sill (geology)|sill]] while the remainder of the seams remained as bituminous coal.<ref>{{cite journal |last1=Darton |first1=Horatio Nelson |title=Guidebook of the Western United States: Part C - The Santa Fe Route, with a side trip to Grand Canyon of the Colorado |journal=U.S. Geological Survey Bulletin |date=1916 |volume=613 |page=81 |doi=10.3133/b613|hdl=2027/hvd.32044055492656 |hdl-access=free }}</ref>

==History==
{{Further|History:History of coal mining}}
[[File:Tiangong Kaiwu Coal Mining.gif|thumb|upright|Chinese coal miners in an illustration of the ''Tiangong Kaiwu'' encyclopedia, published in 1637]]

The earliest recognized use is from the Shenyang area of China where by 4000 BC [[History:Neolithic|Neolithic]] inhabitants had begun carving ornaments from black lignite.<ref>Golas, Peter J and Needham, Joseph (1999) ''Science and Civilisation in China''. Cambridge University Press. pp. 186–91. {{ISBN|0-521-58000-5}}</ref> Coal from the Fushun mine in northeastern China was used to smelt [[Chemistry:Copper|copper]] as early as 1000 BC.<ref>[https://www.britannica.com/EBchecked/topic/122863/coal coal] {{webarchive|url=https://web.archive.org/web/20150502202950/https://www.britannica.com/EBchecked/topic/122863/coal |date=2 May 2015 }}. Encyclopædia Britannica.</ref> Marco Polo, the Italian who traveled to China in the 13th century, described coal as "black stones&nbsp;... which burn like logs", and said coal was so plentiful, people could take three hot baths a week.<ref>[http://factsanddetails.com/china.php?itemid=47&catid=2 Marco Polo In China]. Facts and Details. Retrieved on 11 May 2013. {{webarchive |url=https://web.archive.org/web/20130921073525/http://factsanddetails.com/china.php?itemid=47&catid=2 |date=21 September 2013 }}</ref> In Europe, the earliest reference to the use of coal as fuel is from the geological treatise ''On Stones'' (Lap. 16) by the Greek scientist [[Biography:Theophrastus|Theophrastus]] (c. 371–287 BC):<ref name = "Mattusch">{{Cite book| first=Mattusch|last= Carol |year=2008| title = Metalworking and Tools| editor-last = Oleson| editor-first= John Peter| work = The Oxford Handbook of Engineering and Technology in the Classical World| publisher = Oxford University Press| isbn= 978-0-19-518731-1| pages= 418–38 (432)}}</ref><ref>{{Cite book|url = https://books.google.com/books?id=qvTDGRMPU5kC|title = Greek Science of the Hellenistic Era: A Sourcebook|first1 = Georgia L.|last1 = Irby-Massie|first2 = Paul T.|last2 = Keyser|publisher = Routledge|year = 2002|at = 9.1 "Theophrastos", p. 228|isbn = 978-0-415-23847-2|url-status=live|archive-date = 5 February 2016|archive-url = https://web.archive.org/web/20160205090207/https://books.google.com/books?id=qvTDGRMPU5kC}}</ref>

{{blockquote|Among the materials that are dug because they are useful, those known as ''anthrakes'' [coals] are made of earth, and, once set on fire, they burn like charcoal [anthrakes]. They are found in Liguria&nbsp;... and in Elis as one approaches Olympia by the mountain road; and they are used by those who work in metals.|Theophrastus, On Stones (16) <ref>"το δ'  εκ  της  κατακαύσεως  ὅμοιον  γίνεται  γη   κεκαυμένη. οὓς  δε  καλοῦσιν  ευθὺς  ἄνθρακας των  ὀρυττομένων  δια  την  χρείαν  εισί  γεώδεις,  ἐκκαίονται  δε και πυροῦνται  καθάπερ  οἱ  ἄνθρακες. εισὶ δε  περί  τε  την Λιγυστικὴν ὅπου  και το  ἤλεκτρον, και  εν  τη  Ήλεία  βαδιζόντων   Όλυμπίαζε   την  δι' ὄρους,  οΐς   και  οἱ  χαλκεΐς   χρῶνται." [https://kb.osu.edu/dspace/bitstream/handle/1811/32541/THEOPHRASTUS_CALEY.pdf?sequence=1 ΠΕΡΙ ΛΙΘΩΝ], p. 21.</ref>}}

{{anchor|outcrop coal}}[[Earth:Outcrop|Outcrop]] coal was used in Britain during the [[History:Bronze Age|Bronze Age]] (3000–2000 BC), where it formed part of funeral pyres.<ref name = "Britannicacoal">Britannica 2004: ''Coal mining: ancient use of outcropping coal''</ref><ref>{{cite book |title=Science and Civilisation in China |url=https://archive.org/details/sciencecivilisat00need_094 |url-access=limited |first2= Peter J |last2=Golas |first1=Joseph |last1=Needham |pages = [https://archive.org/details/sciencecivilisat00need_094/page/n204 186]–91 | publisher =Cambridge University Press |year=1999 |isbn= 978-0-521-58000-7}}</ref> In Roman Britain, with the exception of two modern fields, "the Romans were exploiting coals in all the major coalfields in {{wipe|England}} and Wales by the end of the second century AD".<ref name="Smith 1997, 322–324">{{cite journal|author=Smith, A.H.V. |year=1997|title=Provenance of Coals from Roman Sites in England and Wales|journal=Britannia|volume=28|pages=297–324 (322–24)|jstor=526770|doi=10.2307/526770|s2cid=164153278 }}</ref> Evidence of trade in coal, dated to about AD 200, has been found at the Roman settlement at Heronbridge, near Chester; and in the Fenlands of East Anglia, where coal from the Midlands was transported via the Car Dyke for use in drying grain.<ref>{{Cite book| last = Salway | first = Peter | year = 2001 | title = A History of Roman Britain|isbn=978-0-19-280138-8 | publisher = Oxford University Press}}</ref> Coal cinders have been found in the hearths of villas and Roman forts, particularly in Northumberland, dated to around AD 400. In the west of England, contemporary writers described the wonder of a permanent brazier of coal on the altar of Minerva at Aquae Sulis (modern day Bath), although in fact easily accessible surface coal from what became the Somerset coalfield was in common use in quite lowly dwellings locally.<ref>Forbes, RJ (1966): ''Studies in Ancient Technology''. Brill Academic Publishers, Boston.</ref> Evidence of coal's use for [[Chemistry:Iron|iron]]-working in the city during the Roman period has been found.<ref>{{cite book| last = Cunliffe| first = Barry W.|  title = Roman Bath Discovered| publisher = Routledge| year = 1984| location = London| pages = 14–15, 194| isbn = 978-0-7102-0196-6}}</ref> In Eschweiler, Rhineland, deposits of [[Earth:Bituminous coal|bituminous coal]] were used by the Romans for the smelting of [[Earth:Iron ore|iron ore]].<ref name="Smith 1997, 322–324"/>

[[File:Men of the Mine- Life at the Coal Face, Britain, 1942 D8263.jpg|thumb|left|Coal miner in Britain, 1942]]
{{anchor|Sea coal}}
No evidence exists of coal being of great importance in Britain before about AD 1000, the [[History:High Middle Ages|High Middle Ages]].<ref name = "TCC">{{cite book|last=Cantril|first=T.C.|title=Coal Mining|publisher=Cambridge University Press|location=Cambridge|year= 1914 | pages = 3–10| oclc =156716838}}</ref> Coal came to be referred to as "seacoal" in the 13th century; the wharf where the material arrived in London was known as Seacoal Lane, so identified in a charter of King Henry III granted in 1253.<ref>{{cite book|title=Oxford English Dictionary|date=1 December 2010|publisher=Oxford University Press|chapter=coal, 5a|title-link=Oxford English Dictionary}}</ref> Initially, the name was given because much coal was found on the shore, having fallen from the exposed coal seams on cliffs above or washed out of underwater coal outcrops,<ref name = "TCC" /> but by the time of [[Biography:Henry VIII of England|Henry VIII]], it was understood to derive from the way it was carried to London by sea.<ref>John Caius, quoted in Cantril (1914).</ref> In 1257–1259, coal from Newcastle upon Tyne was shipped to London for the [[Engineering:Metalsmith|smiths]] and [[Chemistry:Lime (material)|lime]]-burners building Westminster Abbey.<ref name = "TCC" /> Seacoal Lane and Newcastle Lane, where coal was unloaded at wharves along the River Fleet, still exist.<ref>{{cite book|last=Trench|first= Richard |author2=Hillman, Ellis|title=London Under London: A Subterranean Guide|publisher=John Murray|location=London|year=1993| edition= Second | page=33|isbn=978-0-7195-5288-5}}</ref>

These easily accessible sources had largely become exhausted (or could not meet the growing demand) by the 13th century, when underground extraction by [[Engineering:Shaft mining|shaft mining]] or adits was developed.<ref name="Britannicacoal" /> The alternative name was "pitcoal", because it came from mines.

Cooking and home heating with coal (in addition to firewood or instead of it) has been done in various times and places throughout human history, especially in times and places where ground-surface coal was available and firewood was scarce, but a widespread reliance on coal for home hearths probably never existed until such a switch in fuels happened in London in the late sixteenth and early seventeenth centuries.<ref name="Goodman-2020">{{Citation |last=Goodman |first=Ruth |year=2020 |title=The Domestic Revolution: How the Introduction of Coal Into Victorian Homes Changed Everything |publisher=Liveright |isbn=978-1631497636 |postscript=.}}</ref> Historian Ruth Goodman has traced the socioeconomic effects of that switch and its later spread throughout Britain<ref name="Goodman-2020"/> and suggested that its importance in shaping the industrial adoption of coal has been previously underappreciated.<ref name="Goodman-2020"/>{{rp|xiv-xix}}

The development of the [[History:Industrial Revolution|Industrial Revolution]] led to the large-scale use of coal, as the [[Physics:Steam engine|steam engine]] took over from the [[Engineering:Water wheel|water wheel]]. In 1700, five-sixths of the world's coal was mined in Britain. Britain would have run out of suitable sites for watermills by the 1830s if coal had not been available as a source of energy.<ref name = "Wrigley">{{Cite book| title = Continuity, Chance and Change: The Character of the Industrial Revolution in England| first = EA| last = Wrigley| isbn = 978-0-521-39657-8| publisher = Cambridge University Press| year = 1990| url = https://archive.org/details/isbn_0521396573}}</ref> In 1947 there were some 750,000 miners in Britain,<ref name="BBC News">{{Cite news | url = http://news.bbc.co.uk/2/hi/business/551544.stm | title = The fall of King Coal | work = BBC News | date = 6 December 1999 | url-status = live | archive-url = https://web.archive.org/web/20160306015837/http://news.bbc.co.uk/2/hi/business/551544.stm | archive-date = 6 March 2016}}</ref> but the last deep coal mine in the UK closed in 2015.<ref>{{cite news |title=UK's last deep coal mine Kellingley Colliery capped off |url=https://www.bbc.com/news/uk-england-york-north-yorkshire-35803048 |work=BBC |date=14 March 2016}}</ref>

A grade between bituminous coal and anthracite was once known as "steam coal" as it was widely used as a fuel for [[Engineering:Steam locomotive|steam locomotive]]s. In this specialized use, it is sometimes known as "sea coal" in the United States.<ref>Funk and Wagnalls, quoted in {{cite book|title=Oxford English Dictionary|publisher=Oxford University Press|year=1989|edition=2|chapter=sea-coal|title-link=Oxford English Dictionary}}</ref> Small "steam coal", also called ''dry small steam nuts'' (DSSN), was used as a fuel for domestic [[Engineering:Water heating|water heating]].

Coal played an important role in industry in the 19th and 20th century. The predecessor of the [[Social:European Union|European Union]], the European Coal and Steel Community, was based on the trading of this commodity.<ref>{{cite web | url = https://carleton.ca/ces/eulearning/history/moving-to-integration/the-european-coal-and-steel-community/ | title = The European Coal and Steel Community | website = EU Learning | publisher = Carleton University School of European Studies | access-date = 14 August 2021 | url-status = live|archive-url=https://web.archive.org/web/20150417011518/http://carleton.ca:80/ces/eulearning/history/moving-to-integration/the-european-coal-and-steel-community/ |archive-date=17 April 2015 }}</ref>

Coal continues to arrive on beaches around the world from both natural erosion of exposed coal seams and windswept spills from cargo ships. Many homes in such areas gather this coal as a significant, and sometimes primary, source of home heating fuel.<ref>{{Cite web|url=https://www.alaskapublic.org/2018/03/22/cost-of-cold-staying-warm-in-homer/|title=Cost of Cold: Staying warm in Homer|last1=Bolton|first1=Aaron|last2=Homer|first2=KBBI-|date=2018-03-22|website=Alaska Public Media|language=en-US|access-date=2019-01-25}}</ref>

==Chemistry==

===Composition===
The composition of coal is reported either as a proximate analysis (moisture, volatile matter, fixed carbon, and ash) or an ultimate analysis (ash, carbon, hydrogen, nitrogen, oxygen, and sulfur). The "volatile matter" does not exist by itself (except for some adsorbed methane) but designates the volatile compounds that are produced and driven off by heating the coal. A typical bituminous coal may have an ultimate analysis on a dry, ash-free basis of 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on a weight basis.<ref name=Perry/>

The composition of ash, given in terms of oxides, varies:<ref name=Perry/>
{| class=wikitable
|+ Ash composition, weight percent
| {{chem2|SiO2}}|| 20–40
|-
| {{chem2|Al2O3}}||10–35
|-
| {{chem2|Fe2O3}}||5–35
|-
| CaO||1–20
|-
| MgO||0.3–4
|-
| {{chem2|TiO2}}||0.5–2.5
|-
| {{chem2|Na2O}} & {{chem2|K2O}}||1–4
|-
| {{chem2|SO3}}||0.1–12<ref>Combines with other oxides to make sulfates.</ref>
|-
|}

Other minor components include:
{| class=wikitable
|+ Average content
! Substance !! Content
|-
| [[Chemistry:Mercury (element)|Mercury]] (Hg)
|align=right| {{val|0.10|0.01|u=[[Physics:Parts-per notation|ppm]]}}<ref name="lab_hg">{{cite web|title=Mercury in coal: a review; Part 1. Geochemistry |author=Ya. E. Yudovich, M.P. Ketris |url=http://www.labtechgroup.com/support/hg-1-yudovich.pdf |archive-url=https://web.archive.org/web/20140901135845/http://www.labtechgroup.com/support/Hg-1-Yudovich.pdf |archive-date=1 September 2014 |date=21 April 2010 |access-date=22 February 2013 |publisher=labtechgroup.com |url-status=dead}}</ref>
|-
| [[Chemistry:Arsenic|Arsenic]] (As)
|align=right| {{nowrap|1.4–71 [[Physics:Parts-per notation|ppm]]}}<ref name="usgs_fs2005">{{cite web|title=Arsenic in Coal|url=http://pubs.usgs.gov/fs/2005/3152/fs2005-3152.pdf|date=28 March 2006|access-date=22 February 2013 |publisher=pubs.usgs.gov|url-status=live|archive-date=9 May 2013|archive-url=https://web.archive.org/web/20130509051812/http://pubs.usgs.gov/fs/2005/3152/fs2005-3152.pdf}}</ref>
|-
| [[Chemistry:Selenium|Selenium]] (Se)
|align=right| {{nowrap|3 [[Physics:Parts-per notation|ppm]]}}<ref name="acs_env">{{cite book|title=Selenium in Our Environment – Trace Elements in the Environment|volume=123|page=96|doi=10.1021/ba-1973-0123.ch006|date=1973|chapter=Selenium in Our {{sic|Enviro|ment|nolink-y}} |series=Advances in Chemistry|last1=Lakin|first1=Hubert W.|isbn=978-0-8412-0185-9}}</ref>
|}

===Coking coal and use of coke to smelt iron===
{{Main|Chemistry:Coke (fuel)}}
[[File:Coke Ovens Abercwmboi.jpg|right|thumb|Coke oven at a smokeless fuel plant in Wales, United Kingdom]]

Coke is a solid carbonaceous residue derived from coking coal (a low-ash, low-sulfur bituminous coal, also known as ''metallurgical coal''), which is used in manufacturing steel and other iron products.<ref name="World Coal Steel">{{cite web|title=How is Steel Produced?|url=https://www.worldcoal.org/coal/uses-coal/how-steel-produced|publisher=[[Organization:World Coal Association|World Coal Association]]|access-date=April 8, 2017|url-status=live|archive-url=https://web.archive.org/web/20170412114829/https://www.worldcoal.org/coal/uses-coal/how-steel-produced|archive-date=12 April 2017|date=2015-04-28}}</ref> Coke is made from coking coal by baking in an oven without oxygen at temperatures as high as 1,000&nbsp;°C, driving off the volatile constituents and fusing together the fixed carbon and residual ash. Metallurgical coke is used as a fuel and as a [[Chemistry:Reducing agent|reducing agent]] in [[Engineering:Smelting|smelting]] iron ore in a [[Engineering:Blast furnace|blast furnace]].<ref>[http://www.steelonthenet.com/cost-bof.html Blast furnace steelmaking cost model] {{webarchive|url=https://web.archive.org/web/20160114013811/http://www.steelonthenet.com/cost-bof.html |date=14 January 2016 }}. Steelonthenet.com. Retrieved on 24 August 2012.</ref>  The carbon monoxide produced by its combustion reduces [[Chemistry:Hematite|hematite]] (an [[Chemistry:Iron oxide|iron oxide]]) to iron.

Waste carbon dioxide is also produced {{nowrap|(<chem id="2Fe2O3 + 3C ">2Fe2O3 + 3C -> 4Fe + 3CO2 </chem>)}} together with [[Chemistry:Pig iron|pig iron]], which is too rich in dissolved carbon so must be treated further to make steel.

Coking coal should be low in ash, [[Chemistry:Sulfur|sulfur]], and [[Chemistry:Phosphorus|phosphorus]], so that these do not migrate to the metal.<ref name="World Coal Steel"/>
The coke must be [[Chemistry:Coke strength after reaction|strong enough]] to resist the weight of overburden in the blast furnace, which is why coking coal is so important in making steel using the conventional route. Coke from coal is grey, hard, and porous and has a heating value of 29.6 MJ/kg. Some coke-making processes produce byproducts, including [[Chemistry:Coal tar|coal tar]], [[Chemistry:Ammonia|ammonia]], light oils, and [[Chemistry:Coal gas|coal gas]].

[[Chemistry:Petroleum coke|Petroleum coke]] (petcoke) is the solid residue obtained in oil refining, which resembles coke but contains too many impurities to be useful in metallurgical applications.

====Use in foundry components {{anchor|Industrial processes}}====
Finely ground bituminous coal, known in this application as sea coal, is a constituent of foundry sand. While the molten metal is in the [[Engineering:Molding (process)|mould]], the coal burns slowly, releasing [[Chemistry:Reducing agent|reducing gases]] at pressure, and so preventing the metal from penetrating the pores of the sand. It is also contained in 'mould wash', a paste or liquid with the same function applied to the mould before casting.<ref>{{cite book|last=Rao|first=P. N.|title=Manufacturing Technology: Foundry, Forming and Welding|publisher=Tata McGraw-Hill|location=New Delhi|year=2007|edition=2|page=107|chapter=Moulding materials|isbn=978-0-07-463180-5}}</ref> Sea coal can be mixed with the clay lining (the "bod") used for the bottom of a [[Engineering:Cupola furnace|cupola furnace]]. When heated, the coal decomposes and the bod becomes slightly friable, easing the process of breaking open holes for tapping the molten metal.<ref>{{cite book|last=Kirk|first=Edward|title=Cupola Furnace – A Practical Treatise on the Construction and Management of Foundry Cupolas|chapter-url=https://archive.org/details/cupolafurnacepra00kirkiala|publisher=Baird|location=Philadelphia|year=1899|page=[https://archive.org/details/cupolafurnacepra00kirkiala/page/95 95]|chapter=Cupola management|oclc=2884198}}</ref>

====Alternatives to coke====
Scrap steel can be recycled in an [[Physics:Electric arc furnace|electric arc furnace]]; and an alternative to making iron by smelting is [[Physics:Direct reduced iron|direct reduced iron]], where any carbonaceous fuel can be used to make sponge or pelletised iron. To lessen carbon dioxide emissions [[Chemistry:Hydrogen|hydrogen]] can be used as the reducing agent<ref>{{Cite news|url=https://www.bloomberg.com/news/articles/2019-08-29/how-hydrogen-could-solve-steel-s-climate-test-and-hobble-coal|title=How Hydrogen Could Solve Steel's Climate Test and Hobble Coal|newspaper=Bloomberg.com|date=29 August 2019|access-date=2019-08-31}}</ref> and [[Biology:Biomass|biomass]] or waste as the source of carbon.<ref>{{cite web |title=Coking Coal for steel production and alternatives |url=https://leard.frontlineaction.org/coking-coal-steel-production-alternatives/ |publisher=Front Line Action on Coal |access-date=1 December 2018}}</ref> Historically, charcoal has been used as an alternative to coke in a blast furnace, with the resultant iron being known as [[Chemistry:Charcoal iron|charcoal iron]].

===Gasification===
Coal gasification, as part of an [[Physics:Integrated gasification combined cycle|integrated gasification combined cycle]] (IGCC) coal-fired power station, is used to produce [[Chemistry:Syngas|syngas]], a mixture of [[Chemistry:Carbon monoxide|carbon monoxide]] (CO) and hydrogen (H<sub>2</sub>) gas to fire gas turbines to produce electricity. Syngas can also be converted into transportation fuels, such as [[Chemistry:Gasoline|gasoline]] and [[Chemistry:Diesel fuel|diesel]], through the [[Chemistry:Fischer–Tropsch process|Fischer–Tropsch process]]; alternatively, syngas can be converted into [[Chemistry:Methanol|methanol]], which can be blended into fuel directly or converted to gasoline via the methanol to gasoline process.<ref>{{cite web |url=http://www.netl.doe.gov/research/coal/energy-systems/gasification/gasifipedia/methanol-to-gasoline |title=Conversion of Methanol to Gasoline |publisher=National Energy Technology Laboratory |access-date=16 July 2014 |url-status=live |archive-url=https://web.archive.org/web/20140717225057/http://www.netl.doe.gov/research/Coal/energy-systems/gasification/gasifipedia/methanol-to-gasoline |archive-date=17 July 2014}}</ref> Gasification combined with Fischer–Tropsch technology was used by the [[Company:Sasol|Sasol]] chemical company of {{wipe|South Africa}} to make chemicals and motor vehicle fuels from coal.<ref>{{Cite news|title=Sasol Is Said to Plan Sale of Its South Africa Coal Mining Unit |url=https://www.bloomberg.com/news/articles/2019-09-18/sasol-is-said-to-plan-sale-of-its-south-africa-coal-mining-unit|newspaper=Bloomberg.com|date=18 September 2019|access-date=2020-05-31}}</ref>

During gasification, the coal is mixed with [[Chemistry:Oxygen|oxygen]] and [[Physics:Steam|steam]] while also being heated and pressurized. During the reaction, oxygen and water molecules [[Chemistry:Redox|oxidize]] the coal into carbon monoxide (CO), while also releasing [[Chemistry:Hydrogen|hydrogen]] gas (H<sub>2</sub>). This used to be done in underground coal mines, and also to make town gas, which was piped to customers to burn for illumination, heating, and cooking.

: 3C (''as Coal'') + O<sub>2</sub> + H<sub>2</sub>O → H<sub>2</sub> + 3CO

If the refiner wants to produce gasoline, the syngas is routed into a Fischer–Tropsch reaction. This is known as indirect coal liquefaction. If hydrogen is the desired end-product, however, the syngas is fed into the water gas shift reaction, where more hydrogen is liberated:

: CO + H<sub>2</sub>O → CO<sub>2</sub> + H<sub>2</sub>

===Liquefaction===
{{Main|Chemistry:Coal liquefaction}}

Coal can be converted directly into [[Chemistry:Synthetic fuel|synthetic fuel]]s equivalent to gasoline or diesel by [[Chemistry:Hydrogenation|hydrogenation]] or [[Chemistry:Carbonization|carbonization]].<ref>{{cite web|url=http://www.netl.doe.gov/research/Coal/energy-systems/gasification/gasifipedia/direct-liquefaction|title=Direct Liquefaction Processes|publisher=National Energy Technology Laboratory|access-date=16 July 2014|url-status=live|archive-date=25 July 2014|archive-url=https://web.archive.org/web/20140725082303/http://www.netl.doe.gov/research/Coal/energy-systems/gasification/gasifipedia/direct-liquefaction}}</ref> Coal liquefaction emits more carbon dioxide than liquid fuel production from crude oil. Mixing in biomass and using CCS would emit slightly less than the oil process but at a high cost.<ref>{{cite journal |title=Economic and environmental analyses of coal and biomass to liquid fuels |journal=Energy |volume=141|pages=76–86|doi=10.1016/j.energy.2017.09.047|year=2017|last1=Liu|first1=Weiguo|last2=Wang|first2=Jingxin|last3=Bhattacharyya|first3=Debangsu |last4=Jiang|first4=Yuan |last5=Devallance|first5=David|doi-access=free}}</ref> State owned China Energy Investment runs a coal liquefaction plant and plans to build 2 more.<ref>{{cite news |title=CHN Energy to build new coal-to-liquid production lines |url=http://en.silkroad.news.cn/2018/0813/106231.shtml |agency=Xinhua News Agency |date=13 August 2018}}</ref>

Coal liquefaction may also refer to the cargo hazard when shipping coal.<ref>{{cite news |title=New IMSBC Code requirements aim to control liquefaction of coal cargoes |url=https://www.hellenicshippingnews.com/new-imsbc-code-requirements-aim-to-control-liquefaction-of-coal-cargoes/ |work=Hellenic Shipping News Worldwide |date=29 November 2018 |access-date=1 December 2018 |archive-date=3 August 2020 |archive-url=https://web.archive.org/web/20200803211939/https://www.hellenicshippingnews.com/new-imsbc-code-requirements-aim-to-control-liquefaction-of-coal-cargoes/ |url-status=dead }}</ref>

===Production of chemicals===
[[File:Coal to chemicals routes diagram.jpg|upright=1.35|thumb|Production of chemicals from coal]]

Chemicals have been produced from coal since the 1950s. Coal can be used as a feedstock in the production of a wide range of chemical fertilizers and other chemical products. The main route to these products was [[Chemistry:Coal gasification|coal gasification]] to produce [[Chemistry:Syngas|syngas]]. Primary chemicals that are produced directly from the syngas include [[Chemistry:Methanol|methanol]], [[Chemistry:Hydrogen|hydrogen]] and [[Chemistry:Carbon monoxide|carbon monoxide]], which are the chemical building blocks from which a whole spectrum of derivative chemicals are manufactured, including olefins, [[Chemistry:Acetic acid|acetic acid]], [[Physics:Formaldehyde|formaldehyde]], ammonia, [[Chemistry:Urea|urea]] and others. The versatility of [[Chemistry:Syngas|syngas]] as a precursor to primary chemicals and high-value derivative products provides the option of using coal to produce a wide range of commodities. In the 21st century, however, the use of [[Chemistry:Coalbed methane|coal bed methane]] is becoming more important.<ref>{{Cite web|title=Coal India begins process of developing Rs 2,474 crore CBM projects {{!}} Hellenic Shipping News Worldwide|url=https://www.hellenicshippingnews.com/coal-india-begins-process-of-developing-rs-2474-crore-cbm-projects/|website=www.hellenicshippingnews.com|access-date=2020-05-31}}</ref>

Because the slate of chemical products that can be made via coal gasification can in general also use feedstocks derived from [[Chemistry:Natural gas|natural gas]] and [[Chemistry:Petroleum|petroleum]], the chemical industry tends to use whatever feedstocks are most cost-effective. Therefore, interest in using coal tended to increase for higher oil and natural gas prices and during periods of high global economic growth that might have strained oil and gas production.

Coal to chemical processes require substantial quantities of water.<ref>{{Cite web|title=Coal-to-Chemicals: Shenhua's Water Grab|url=http://www.chinawaterrisk.org/opinions/coal-to-chemicals-shenhuas-water-grab-2/|website=China Water Risk|language=en-US|access-date=2020-05-31}}</ref> Much coal to chemical production is in China<ref name=OILDRUM9371>{{cite web|title=China's Coal to Chemical Future|url=http://www.theoildrum.com/node/9371|publisher=The Oil Drum.Com|access-date=3 March 2013|author=Rembrandt|format=Blog post by expert|date=2 August 2012}}</ref><ref name=ICIS022712>{{cite news|title=China develops coal-to-olefins projects, which could lead to ethylene self-sufficiency|url=http://www.icis.com/Articles/2012/02/27/9535534/china-develops-coal-to-olefins-projects-which-could-lead-to-ethylene.html|author= Yin, Ken|access-date=3 March 2013|newspaper=ICIS Chemical Business|date=27 February 2012}}</ref> where coal dependent provinces such as Shanxi are struggling to control its pollution.<ref>{{cite news |title=Smog war casualty: China coal city bears brunt of pollution crackdown |url=https://www.reuters.com/article/us-china-pollution-economy-insight/smog-war-casualty-china-coal-city-bears-brunt-of-pollution-crackdown-idUSKCN1NV2RB |work={{wipe|Reuters}} |date=27 November 2018}}</ref>

==Electricity generation==

===Energy density===
{{Main|Physics:Energy value of coal}}

The [[Physics:Energy density|energy density]] of coal is roughly 24 megajoules per kilogram<ref>{{cite web |last=Fisher |first=Juliya |title=Energy Density of Coal |work=The Physics Factbook |year=2003 |url=http://hypertextbook.com/facts/2003/JuliyaFisher.shtml |access-date=25 August 2006 |archive-url=https://web.archive.org/web/20061107152122/http://hypertextbook.com/facts/2003/JuliyaFisher.shtml |archive-date=7 November 2006 |url-status=live}}</ref> (approximately 6.7 kilowatt-hours per kg). For a coal power plant with a 40% efficiency, it takes an estimated {{convert|325|kg|abbr=on}} of coal to power a 100&nbsp;W lightbulb for one year.<ref>{{cite web| title=How much coal is required to run a 100-watt light bulb 24 hours a day for a year?| work=Howstuffworks| url=http://science.howstuffworks.com/question481.htm| date=2000-10-03| access-date = 25 August 2006| url-status=live| archive-date=7 August 2006| archive-url=https://web.archive.org/web/20060807235142/http://science.howstuffworks.com/question481.htm}}</ref>

27.6% of world energy was supplied by coal in 2017 and Asia used almost three-quarters of it.<ref>{{cite web |title=Primary energy |url=https://www.bp.com/en/global/corporate/energy-economics/statistical-review-of-world-energy/primary-energy.html |publisher=[[Company:BP|BP]] |access-date=5 December 2018}}</ref>

===Precombustion treatment===
Refined coal is the product of a coal-upgrading technology that removes moisture and certain pollutants from lower-rank coals such as sub-bituminous and lignite (brown) coals. It is one form of several precombustion treatments and processes for coal that alter coal's characteristics before it is burned. [[Physics:Thermal efficiency|Thermal efficiency]] improvements are achievable by improved pre-drying (especially relevant with high-moisture fuel such as lignite or biomass).<ref>{{cite web | title = The Niederraussem Coal Innovation Centre | publisher = RWE | url = http://www.rwe.com/web/cms/mediablob/en/234504/data/2378/5/rwe-power-ag/innovations/coal-innovation-centre/Brochure-The-Niederaussem-Coal-Innovation-Centre.pdf | access-date = 21 July 2014 | url-status = live | archive-url = https://web.archive.org/web/20130722025133/http://www.rwe.com/web/cms/mediablob/en/234504/data/2378/5/rwe-power-ag/innovations/coal-innovation-centre/Brochure-The-Niederaussem-Coal-Innovation-Centre.pdf | archive-date = 22 July 2013}}</ref> The goals of precombustion coal technologies are to increase efficiency and reduce emissions when the coal is burned. Precombustion technology can sometimes be used as a supplement to postcombustion technologies to control emissions from coal-fueled boilers.

===Power plant combustion===
{{Main|Finance:Coal-fired power station}}
[[File:Grand Junction Trip 92007 098.JPG|thumb|Castle Gate Power Plant near Helper, Utah, US]]
[[File:Ashtabulacoalcars e2.jpg|thumb|Coal rail cars]]
[[File:Komatsu bulldozer pushing coal in Power plant Ljubljana (winter 2017).jpg|thumb|[[Engineering:Bulldozer|Bulldozer]] pushing coal in Ljubljana Power Station, Slovenia]]
Coal burnt as a [[Chemistry:Solid fuel|solid fuel]] in coal power stations to [[Engineering:Electricity generation|generate electricity]] is called '''thermal coal'''. Coal is also used to produce very high temperatures through combustion. Early deaths due to air pollution have been estimated at 200 per GW-year, however they may be higher around power plants where scrubbers are not used or lower if they are far from cities.<ref>{{Cite web|url=http://berkeleyearth.org/deaths-per-gigawatt-year/|title=Coal in China: Estimating Deaths per GW-year|date=2016-11-18|website=Berkeley Earth|language=en-US|access-date=2020-02-01}}</ref> Efforts around the world to reduce the use of coal have led some regions to switch to natural gas and electricity from lower carbon sources.

When coal is used for [[Engineering:Electricity generation|electricity generation]], it is usually pulverized and then burned in a furnace with a [[Engineering:Boiler|boiler]] (see also [[Physics:Pulverized coal-fired boiler|Pulverized coal-fired boiler]]).<ref name="World Coal">[http://www.worldcoal.org/coal/uses-of-coal/coal-electricity/ Total World Electricity Generation by Fuel (2006)] {{webarchive|url=https://web.archive.org/web/20151022093430/http://www.worldcoal.org/coal/uses-of-coal/coal-electricity/ |date=22 October 2015}}. Source: IEA 2008.</ref> The furnace heat converts boiler water to [[Physics:Steam|steam]], which is then used to spin [[Physics:Turbine|turbine]]s which turn [[Engineering:Electrical generator|generators]] and create electricity.<ref>{{cite web |title=Fossil Power Generation |publisher=Siemens AG |url=http://w1.siemens.com/responsibility/en/environment/portfolio/fossil_power_generation.htm|archive-url= http://arquivo.pt/wayback/20090929225531/http://w1.siemens.com/responsibility/en/environment/portfolio/fossil_power_generation.htm |url-status=dead |archive-date=29 September 2009 |access-date=23 April 2009}}</ref> The thermodynamic efficiency of this process varies between about 25% and 50% depending on the pre-combustion treatment, turbine technology (e.g. [[Engineering:Supercritical steam generator|supercritical steam generator]]) and the age of the plant.<ref>J. Nunn, A. Cottrell, A. Urfer, L. Wibberley and P. Scaife, [http://www.docstoc.com/docs/80110435/TA-28-Vic-elec-grid-YED-2000-Final "A Lifecycle Assessment of the Victorian Energy Grid"] {{webarchive|url=https://web.archive.org/web/20160902132119/http://www.docstoc.com/docs/80110435/TA-28-Vic-elec-grid-YED-2000-Final |date=2 September 2016 }}, Cooperative Research Centre for Coal in Sustainable Development, February 2003, p. 7.</ref><ref>{{cite web |title=Neurath F and G set new benchmarks |publisher=Alstom |url=http://www.alstom.com/Global/Power/Resources/Documents/Brochures/neurath-fandg-supercritical-steam-power-plant-new-benchmarks.pdf |access-date=21 July 2014 |url-status=live |archive-url=https://web.archive.org/web/20150401132704/http://www.alstom.com/Global/Power/Resources/Documents/Brochures/neurath-fandg-supercritical-steam-power-plant-new-benchmarks.pdf |archive-date=1 April 2015}}</ref>

A few [[Physics:Integrated gasification combined cycle|integrated gasification combined cycle]] (IGCC) power plants have been built, which burn coal more efficiently. Instead of pulverizing the coal and burning it directly as fuel in the steam-generating boiler, the [[Chemistry:Coal gasification|coal is gasified]] to create [[Chemistry:Syngas|syngas]], which is burned in a [[Engineering:Gas turbine|gas turbine]] to produce electricity (just like natural gas is burned in a turbine). Hot exhaust gases from the turbine are used to raise steam in a heat recovery steam generator which powers a supplemental [[Engineering:Steam turbine|steam turbine]]. The overall plant efficiency when used to provide [[Physics:Combined heat and power|combined heat and power]] can reach as much as 94%.<ref>[http://ipaper.ipapercms.dk/DONGENERGY/Internet/UK/ThermalPower/AVVbrochure2012UK/ Avedøreværket] {{webarchive|url=https://web.archive.org/web/20160129110317/http://ipaper.ipapercms.dk/DONGENERGY/Internet/UK/ThermalPower/AVVbrochure2012UK/ |date=29 January 2016 }}. Ipaper.ipapercms.dk. Retrieved on 11 May 2013.</ref> IGCC power plants emit less local pollution than conventional pulverized coal-fueled plants; however the technology for [[Physics:Carbon capture and storage|carbon capture and storage]] (CCS) after gasification and before burning has so far proved to be too expensive to use with coal.<ref>{{cite news |title=DOE Sank Billions of Fossil Energy R&D Dollars in CCS Projects. Most Failed. |url=https://www.powermag.com/doe-sank-billions-of-fossil-energy-rd-dollars-in-ccs-projects-most-failed/ |work=PowerMag |date=9 October 2018}}</ref><ref>{{cite magazine |author1=Jennie C. Stephens |author2=Bob van der Zwaan |date=Fall 2005 |url=https://issues.org/stephens/ |title=The Case for Carbon Capture and Storage |magazine=Issues in Science and Technology |volume=XXII |issue=1}}</ref> Other ways to use coal are as coal-water slurry fuel (CWS), which was developed in the [[Place:Soviet Union|Soviet Union]], or in [[Physics:Magnetohydrodynamic generator|an MHD topping cycle]]. However these are not widely used due to lack of profit.

In 2017 38% of the world's electricity came from coal, the same percentage as 30 years previously.<ref>{{cite web |title=The most depressing energy chart of the year |url=https://www.vox.com/energy-and-environment/2018/6/15/17467164/energy-chart-renewables-coal-climate-change |publisher=Vox |access-date=30 October 2018|date=2018-06-15 }}</ref> In 2018 global installed capacity was 2[[Terawatt|TW]] (of which 1TW is in China) which was 30% of total electricity generation capacity.<ref name="Cornot-Gandolfe 2018" /> The most dependent major country is South Africa, with over 80% of its electricity generated by coal;<ref>{{cite web |title=Energy Revolution: A Global Outlook |url=https://www.drax.com/wp-content/uploads/2018/12/Energy-Revolution-Global-Outlook-Report-Final-Dec-2018-COP24.pdf |archive-url=https://web.archive.org/web/20190209123738/https://www.drax.com/wp-content/uploads/2018/12/Energy-Revolution-Global-Outlook-Report-Final-Dec-2018-COP24.pdf |archive-date=2019-02-09 |url-status=live |publisher=Drax |access-date=7 February 2019}}</ref> but China alone generates more than half of the world's coal-generated electricity.<ref>{{cite news |title=China generated over half world's coal-fired power in 2020: study |url=https://www.reuters.com/article/us-climate-change-china-coal/china-generated-over-half-worlds-coal-fired-power-in-2020-study-idUSKBN2BK0PZ |access-date=14 September 2021 |work={{wipe|Reuters}} |date=28 March 2021 |quote=China generated 53% of the world’s total coal-fired power in 2020, nine percentage points more that five years earlier}}</ref>

Maximum use of coal was reached in 2013.<ref name="2019_overview">{{Cite web|url=https://webstore.iea.org/login?ReturnUrl=%2fdownload%2fdirect%2f2542%3ffileName%3dCoal_Information_2019_Overview.pdf&fileName=Coal_Information_2019_Overview.pdf|title=Coal Information Overview 2019|publisher=[[Organization:International Energy Agency|International Energy Agency]]|quote=peak production in 2013|page=3|access-date=28 March 2020|archive-date=30 September 2020|archive-url=https://web.archive.org/web/20200930040043/https://webstore.iea.org/login?ReturnUrl=%2Fdownload%2Fdirect%2F2542%3FfileName%3DCoal_Information_2019_Overview.pdf&fileName=Coal_Information_2019_Overview.pdf|url-status=dead}}</ref> In 2018 coal-fired power station [[Engineering:Capacity factor|capacity factor]] averaged 51%, that is they operated for about half their available operating hours.<ref>{{Cite report|url=https://endcoal.org/wp-content/uploads/2020/03/BoomAndBust_2020_English.pdf|title=Boom and Bust 2020: Tracking the Global Coal Plant Pipeline|last1=Shearer|first1=Christine|last2=Myllyvirta|first2=Lauri|date=March 2020|publisher=[[Organization:Global Energy Monitor|Global Energy Monitor]]|last3=Yu|first3=Aiqun|last4=Aitken|first4=Greig|last5=Mathew-Shah|first5=Neha|last6=Dallos|first6=Gyorgy|last7=Nace|first7=Ted|access-date=27 April 2020|archive-date=27 March 2020|archive-url=https://web.archive.org/web/20200327062155/https://endcoal.org/wp-content/uploads/2020/03/BoomAndBust_2020_English.pdf|url-status=dead}}</ref>

==Coal industry==

===Mining===
About 8000 Mt of coal are produced annually, about 90% of which is hard coal and 10% lignite. {{As of|2018}} just over half is from underground mines.<ref>{{cite web |title=Coal mining |url=https://www.worldcoal.org/coal/coal-mining |publisher=[[Organization:World Coal Association|World Coal Association]] |access-date=5 December 2018|date=2015-04-28 }}</ref> More accidents occur during underground mining than surface mining. Not all countries publish mining accident statistics so worldwide figures are uncertain, but it is thought that most deaths occur in coal mining accidents in China: in 2017 there were 375 coal mining related deaths in China.<ref>{{cite news |title=China: seven miners killed after skip plummets down mine shaft |url=https://www.theguardian.com/world/2018/dec/16/miners-killed-in-south-west-china-mining-accident |newspaper={{wipe|The Guardian}} |date=16 December 2018|agency=Agence France-Presse }}</ref> Most coal mined is thermal coal (also called steam coal as it is used to make steam to generate electricity) but metallurgical coal (also called "metcoal" or "coking coal" as it is used to make coke to make iron) accounts for 10% to 15% of global coal use.<ref>{{cite magazine |title=The One Market That's Sure To Help Coal |url=https://www.forbes.com/sites/judeclemente/2018/08/12/the-one-market-thats-sure-to-help-coal/#570c071f6f6e |magazine={{wipe|Forbes}} |date=12 August 2018}}</ref>

===As a traded commodity===
{{See also|Cost of electricity by source}}[[File:Art work of Toledo, Ohio - DPLA - 0a107364e8d8eb430ebc183d28c46463 (page 125) (cropped).jpg|thumb|right|Extensive coal docks seen in Toledo, Ohio, 1895]]
China mines almost half the world's coal, followed by India with about a tenth.<ref name="BPReview2016"/> Australia accounts for about a third of world coal exports, followed by Indonesia and Russia,<ref name=":1">{{Cite journal |last1=Overland |first1=Indra |last2=Loginova |first2=Julia |date=2023-08-01 |title=The Russian coal industry in an uncertain world: Finally pivoting to Asia? |journal=Energy Research & Social Science |volume=102 |pages=103150 |doi=10.1016/j.erss.2023.103150 |issn=2214-6296|doi-access=free }}</ref><ref name=":2" /> while the largest importers are Japan and India. Russia is increasingly orienting its coal exports from Europe to Asia as Europe transitions to renewable energy and subjects Russia to sanctions over its invasion of Ukraine.<ref>{{Cite journal |last1=Overland |first1=Indra |last2=Loginova |first2=Julia |date=2023-08-01 |title=The Russian coal industry in an uncertain world: Finally pivoting to Asia? |journal=Energy Research & Social Science |volume=102 |pages=103150 |doi=10.1016/j.erss.2023.103150 |issn=2214-6296|doi-access=free }}</ref>

The price of metallurgical coal is volatile<ref>{{cite web |title=Coal 2017 |url=https://eneken.ieej.or.jp/data/7732.pdf |archive-url=https://web.archive.org/web/20180620012116/http://eneken.ieej.or.jp/data/7732.pdf |archive-date=2018-06-20 |url-status=live |publisher=[[Organization:International Energy Agency|IEA]] |access-date=26 November 2018}}</ref> and much higher than the price of thermal coal because metallurgical coal must be lower in sulfur and requires more cleaning.<ref>{{cite web |title=Coal Prices and Outlook |url=https://www.eia.gov/energyexplained/index.php?page=coal_prices |publisher=U.S. Energy Information Administration}}</ref> Coal futures contracts provide coal producers and the [[Physics:Electric power industry|electric power industry]] an important tool for [[Finance:Hedge|hedging]] and [[Risk management|risk management]].

In some countries, new onshore wind or [[Engineering:Solar power|solar]] generation already costs less than coal power from existing plants.<ref>{{Cite news| title = New wind and solar generation costs fall below existing coal plants |work=Financial Times| access-date = 2018-11-08| url = https://www.ft.com/content/af6915c8-e2eb-11e8-a6e5-792428919cee}}</ref><ref>{{cite web |title=Lazard's Levelized Cost of Energy ('LCOE') analysis – Version 12.0 |url=https://www.lazard.com/media/450773/lazards-levelized-cost-of-energy-version-120-vfinal.pdf |archive-url=https://web.archive.org/web/20181109235056/https://www.lazard.com/media/450773/lazards-levelized-cost-of-energy-version-120-vfinal.pdf |archive-date=2018-11-09 |url-status=live |access-date=9 November 2018}}</ref> 
However, for China this is forecast for the early 2020s<ref name="CarbTrk2018">{{cite web |title=40% of China's coal power stations are losing money |url=https://www.carbontracker.org/40-of-chinas-coal-power-stations-are-losing-money/ |publisher=Carbon Tracker |access-date=11 November 2018|date=2018-10-11 }}</ref> and for southeast Asia not until the late 2020s.<ref>{{cite web |title=Economic and financial risks of coal power in Indonesia, Vietnam and the Philippines |url=https://www.carbontracker.org/reports/economic-and-financial-risks-of-coal-power-in-indonesia-vietnam-and-the-philippines/ |publisher=Carbon Tracker |access-date=9 November 2018}}</ref> In India, building new plants is uneconomic and, despite being subsidized, existing plants are losing market share to renewables.<ref>{{cite news |title=India's Coal Paradox |url=https://oilprice.com/Energy/Coal/Indias-Coal-Paradox.html |date=5 January 2019}}</ref>

===Market trends===
Of the [[Chemistry:List of countries by coal production|countries which produce coal]], China mines by far the most, almost half the world's coal, followed by less than 10% by India. China is also by far the largest consumer of coal. Therefore, international market trends depend on Chinese energy policy.<ref name=IEA2018>{{cite web |title=Coal 2018:Executive Summary |url=https://webstore.iea.org/download/summary/2415 |publisher=[[Organization:International Energy Agency|International Energy Agency]] |date=2018 |access-date=18 December 2018 |archive-date=18 December 2018 |archive-url=https://web.archive.org/web/20181218193720/https://webstore.iea.org/download/summary/2415 |url-status=dead }}</ref> Although the government effort to reduce air pollution in China means that the global long-term trend is to burn less coal, the short and medium term trends may differ, in part due to Chinese financing of new coal-fired power plants in other countries.<ref name="Cornot-Gandolfe 2018">{{cite book |last1=Cornot-Gandolfe |first1=Sylvie |title=A Review of Coal Market Trends and Policies in 2017|date=May 2018 |publisher=Ifri |url=https://www.ifri.org/sites/default/files/atoms/files/cornot_gandolphe_coal_exit_2018.pdf |archive-url=https://web.archive.org/web/20181115153650/https://www.ifri.org/sites/default/files/atoms/files/cornot_gandolphe_coal_exit_2018.pdf |archive-date=2018-11-15 |url-status=live}}</ref>

===Major producers===
{{Main|Chemistry:List of countries by coal production}}
[[File:Coal production by region, OWID.svg|thumb|upright=1.8|Coal production by region]]
Countries with annual production higher than 300 million tonnes are shown.
{| class="wikitable sortable" style="text-align:right;"
|+ Production of coal by country and year (million tonnes)<ref name="BPReview2011">{{cite web|url=http://www.bp.com/assets/bp_internet/globalbp/globalbp_uk_english/reports_and_publications/statistical_energy_review_2011/STAGING/local_assets/spreadsheets/statistical_review_of_world_energy_full_report_2012.xlsx |title=BP Statistical review of world energy 2012 |publisher=British Petroleum |format=XLS |access-date=18 August 2011 |url-status=dead |archive-date=19 June 2012 |archive-url=https://web.archive.org/web/20120619171812/http://www.bp.com/assets/bp_internet/globalbp/globalbp_uk_english/reports_and_publications/statistical_energy_review_2011/STAGING/local_assets/spreadsheets/statistical_review_of_world_energy_full_report_2012.xlsx}}</ref><ref name="BPReview2016">{{cite web |url=http://www.bp.com/content/dam/bp/excel/energy-economics/statistical-review-2016/bp-statistical-review-of-world-energy-2016-workbook.xlsx |title=BP Statistical review of world energy 2016 |publisher=British Petroleum |format=XLS |access-date=8 February 2017 |url-status=live |archive-date=2 December 2016 |archive-url=https://web.archive.org/web/20161202103642/http://www.bp.com/content/dam/bp/excel/energy-economics/statistical-review-2016/bp-statistical-review-of-world-energy-2016-workbook.xlsx}}</ref><ref name=BP2018>{{cite web |title=BP Statistical Review of World Energy 2018 |publisher=British Petroleum |url=https://www.bp.com/content/dam/bp/en/corporate/pdf/energy-economics/statistical-review/bp-stats-review-2018-coal.pdf |archive-url=https://web.archive.org/web/20181206170529/https://www.bp.com/content/dam/bp/en/corporate/pdf/energy-economics/statistical-review/bp-stats-review-2018-coal.pdf |archive-date=2018-12-06 |url-status=live |access-date=6 December 2018}}</ref><ref name="IEAstats">{{cite web|title=Global energy data |url=https://www.iea.org/statistics|publisher=[[Organization:International Energy Agency|International Energy Agency]]}}</ref>
|-
! Country
! 2000
! 2005
! 2010
! 2015
! 2017
! Share (2017)
|-
|align="left"|China
| 1,384
| 2,350
| 3,235
| 3,747
| 3,523
| 46%
|-
|align="left"|India
| 335
| 429
| 574
| 678
| 716
| 9%
|-
|align="left"|United States
| 974
| 1,027
| 984
| 813
| 702
| 9%
|-
|align="left"|Australia
| 314
| 375
| 424
| 485
| 481
| 6%
|-
|align="left"|Indonesia
| 77
| 152
| 275
| 392
| 461
| 6%
|-
|align="left"|Russia
| 262
| 298
| 322
| 373
| 411
| 5%
|-
|align="left"|Rest of World
| 1380
| 1404
| 1441
| 1374
| 1433
| 19%
|- class="sortbottom"
! World total
! 4,726
! 6,035
! 7,255
! 7,862
! 7,727
! 100%
|}

===Major consumers===
Countries with annual consumption higher than 500 million tonnes are shown. Shares are based on data expressed in tonnes oil equivalent.

{| class="wikitable sortable" style="text-align:right;"
|+ Consumption of coal by country and year (million tonnes)<ref>[http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=1&pid=1&aid=2 EIA International Energy Annual – Total Coal Consumption (Thousand Short Tons – converted to metric)] {{webarchive|url=https://web.archive.org/web/20160209123924/http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=1&pid=1&aid=2 |date=9 February 2016 }}. Eia.gov. Retrieved on 11 May 2013.</ref><ref>[https://www.eia.gov/beta/international/data/browser/#/?pa=00000000000000000000000000000000000000000080000000008&c=000000020000000000000800000000000000000000000002&ct=0&ug=8&tl_id=1-A&vs=INTL.7-2-CHN-MT.A&vo=0&v=H&end=2016 Coal Consumption]</ref>
|-
! Country
! 2008
! 2009
! 2010
! 2011
! 2012
! 2013
! 2014
! 2015
! 2016
! Share
|-
|align="left"|China
| 2,691
| 2,892
| 3,352
| 3,677
| 4,538
| 4,678
| 4,539
| 3,970 coal + 441 met coke = 4,411
| 3,784 coal + 430 met coke = 4,214
| 51%
|-
|align="left"|India
| 582
| 640
| 655
| 715
| 841
| 837
| 880
| 890 coal + 33 met coke = 923
| 877 coal + 37 met coke = 914
| 11%
|-
|align="left"|United States
| 1,017
| 904
| 951
| 910
| 889
| 924
| 918
| 724 coal + 12 met coke = 736
| 663 coal + 10 met coke = 673
| 9%
|- class="sortbottom"
! World Total
! 7,636
! 7,699
! 8,137
! 8,640
! 8,901
! 9,013
! 8,907
! 7,893 coal + 668 met coke = 8561
! 7,606 coal + 655 met coke = 8261
! 100%
|}

===Major exporters===
{| class="wikitable sortable" style="margin:auto; text-align:right;"
|+ Exports of coal by country and year (million tonnes)<ref>{{cite web |title=Primary Coal Exports |url=https://www.eia.gov/international/data/world/coal-and-coke/coal-and-coke-exports |publisher=US Energy Information Administration |access-date=12 May 2023}}</ref>
|-
!Country
!2018
!2019
!2020
!2021
|-
!Indonesia
|408
|443
|410
|434
|-
!Australia
|382
|393
|371
|366
|-
!Russia
|212
|223
|222
|238
|-
!United States
|105
|85
|63
|77
|-
!South Africa
|80
|79
|75
|66
|-
!Colombia
|84
|72
|68
|56
|-
!Canada
|32
|36
|32
|32
|-
!Netherlands
|30
|28
|15
|27
|-
!Kazakhstan
|26
|26
|25
|24
|-
!Mongolia
|36
|36
|29
|20
|}

Exporters are at risk of a reduction in import demand from India and China.<ref name="IDDRI">{{cite book|url=https://www.iddri.org/sites/default/files/PDF/Publications/Catalogue%20Iddri/Rapport/201809-GlobalModelingReport-Iddri-Coal_FINAL.pdf |archive-url=https://web.archive.org/web/20181101015312/https://www.iddri.org/sites/default/files/PDF/Publications/Catalogue%20Iddri/Rapport/201809-GlobalModelingReport-Iddri-Coal_FINAL.pdf |archive-date=2018-11-01 |url-status=live|title=What Does "Peak Coal" Mean for International Coal Exporters?|date=2018}}</ref><ref name=":1" />

===Major importers===
{| class="wikitable sortable" style="margin:auto; text-align:right;"
|+ Imports of coal by country and year (million tonnes)<ref>{{cite web |title=Primary Coal Imports |url=https://www.eia.gov/beta/international/data/browser/#/?pa=00000000000000000000000000000000000000000020000000004&c=00000002000g00000000080g4000000000000000000000k&ct=0&ug=8&tl_id=1-A&vs=INTL.7-3-CHN-MT.A&vo=0&v=H |publisher=US Energy Information Administration |access-date=26 July 2020}}</ref><ref>{{cite web|title=Energy Statistical annual Reports| date=4 May 2012 |url=https://www.moeaboe.gov.tw/ECW/english/content/ContentLink.aspx?menu_id=1540|publisher=Taiwan Bureau of Energy, Ministry of Economic Affairs|access-date=26 July 2020}}</ref>
|-
! style="width:140pt;"|Country
! style="width:100pt;"|2018
|-
|align="left"|China
| 281
|-
|align="left"|India
| 223
|-
|align="left"|Japan
| 189
|-
|align="left"|South Korea
| 149
|-
|align="left"|Taiwan
| 76
|-
|align="left"|Germany
| 44
|-
|align="left"|Netherlands
| 44
|-
|align="left"|Turkey
| 38
|-
|align="left"|Malaysia
| 34
|-
|align="left"|Thailand
| 25
|}

==Damage to human health{{anchor|Health_effects}}==

The use of coal as fuel causes ill health and deaths.<ref>[http://www.lungusa.org/assets/documents/healthy-air/toxic-air-report.pdf Toxic Air: The Case for Cleaning Up Coal-fired Power Plants]. American Lung Association (March 2011) {{webarchive |url=https://web.archive.org/web/20120126123239/http://www.lungusa.org/assets/documents/healthy-air/toxic-air-report.pdf |date=26 January 2012 }}</ref> Mining and processing of coal causes air and water pollution.<ref name=":0">{{Cite journal|last1=Hendryx|first1=Michael|last2=Zullig|first2=Keith J.|last3=Luo|first3=Juhua|date=2020-01-08|title=Impacts of Coal Use on Health|journal=Annual Review of Public Health|volume=41 |doi=10.1146/annurev-publhealth-040119-094104|pmid=31913772|issn=0163-7525|doi-access=free|pages=397–415}}</ref> Coal-powered plants emit nitrogen oxides, sulfur dioxide, particulate pollution and heavy metals, which adversely affect human health.<ref name=":0" /> [[Chemistry:Coalbed methane extraction|Coal bed methane extraction]] is important to avoid mining accidents.

The deadly [[Earth:Pea soup fog#London|London smog]] was caused primarily by the heavy use of coal. Globally coal is estimated to cause 800,000 premature deaths every year,<ref name="Endcoal health">{{cite web |title=Health |url=https://endcoal.org/health/ |publisher=Endcoal |access-date=3 December 2018 |archive-date=22 December 2017 |archive-url=https://web.archive.org/web/20171222052743/https://endcoal.org/health/ |url-status=dead }}</ref> mostly in India<ref name=Economist2018>{{cite news |title=India shows how hard it is to move beyond fossil fuels |newspaper=The Economist |url=https://www.economist.com/briefing/2018/08/02/india-shows-how-hard-it-is-to-move-beyond-fossil-fuels |date=2 August 2018}}</ref> and China.<ref>[https://www.who.int/quantifying_ehimpacts/publications/preventing-disease/en/ Preventing disease through healthy environments: a global assessment of the burden of disease from environmental risks] {{webarchive|url=https://web.archive.org/web/20160730124831/http://www.who.int/quantifying_ehimpacts/publications/preventing-disease/en/ |date=30 July 2016 }}. World Health Organization (2006)</ref><ref>{{cite book |url=https://www.who.int/healthinfo/global_burden_disease/GlobalHealthRisks_report_full.pdf|isbn=978-92-4-156387-1|date=2009|publisher=World Health Organization|title=Global Health Risks: Mortality and Burden of Disease Attributable to Selected Major Risks|url-status=live|archive-url=https://web.archive.org/web/20120214111235/http://www.who.int/healthinfo/global_burden_disease/GlobalHealthRisks_report_full.pdf|archive-date=14 February 2012}}</ref><ref>{{cite web|url=https://www.who.int/mediacentre/factsheets/fs313/en/ |title=WHO – Ambient (outdoor) air quality and health |work=who.int |access-date=7 January 2016 |url-status=dead |archive-date=4 January 2016 |archive-url=https://web.archive.org/web/20160104165807/http://www.who.int/mediacentre/factsheets/fs313/en/}}</ref>

Burning coal is a major contributor to [[Chemistry:Sulfur dioxide|sulfur dioxide]] emissions, which creates PM2.5 [[Earth:Particulates|particulates]], the most dangerous form of air pollution.<ref>{{Cite news|url=https://storage.googleapis.com/planet4-international-stateless/2019/08/e40af3dd-global-hotspot-and-emission-sources-for-so2_16_august-2019.pdf |archive-url=https://web.archive.org/web/20191003074644/https://storage.googleapis.com/planet4-international-stateless/2019/08/e40af3dd-global-hotspot-and-emission-sources-for-so2_16_august-2019.pdf |archive-date=2019-10-03 |url-status=live|title=Global SO2 emission hotspot database|date=August 2019|publisher=Greenpeace}}</ref>

Coal smokestack emissions cause [[Medicine:Asthma|asthma]], strokes, reduced [[Philosophy:Intelligence|intelligence]], [[Biology:Artery|artery]] blockages, heart attacks, congestive heart failure, cardiac arrhythmias, [[Medicine:Mercury poisoning|mercury poisoning]], [[Medicine:Stenosis|arterial occlusion]], and lung cancer.<ref name="psr_coal-damages-health">[http://www.psr.org/news-events/press-releases/coal-pollution-damages-human-health.html Coal Pollution Damages Human Health at Every Stage of Coal Life Cycle, Reports Physicians for Social Responsibility] {{webarchive|url=https://web.archive.org/web/20150731182839/http://www.psr.org/news-events/press-releases/coal-pollution-damages-human-health.html |date=31 July 2015 }}. ''Physicians for Social Responsibility''. psr.org (18 November 2009)</ref><ref>Burt, Erica; Orris, Peter and Buchanan, Susan (April 2013) [http://noharm.org/lib/downloads/climate/Coal_Literature_Review_2.pdf Scientific Evidence of Health Effects from Coal Use in Energy Generation] {{webarchive|url=https://web.archive.org/web/20150714193454/http://noharm.org/lib/downloads/climate/Coal_Literature_Review_2.pdf |date=14 July 2015 }}. University of Illinois at Chicago School of Public Health, Chicago, Illinois, US</ref>

Annual health costs in Europe from use of coal to generate electricity are estimated at up to €43 billion.<ref>{{cite web|title=The Unpaid Health Bill – How coal power plants make us sick|url=https://www.env-health.org/unpaid-health-bill-how-coal-power-plants-make-us-sick/|publisher=Health and Environment Alliance|access-date=15 December 2018|date=2013-03-07}}</ref>

In China, improvements to air quality and human health would increase with more stringent climate policies, mainly because the country's energy is so heavily reliant on coal. And there would be a net economic benefit.<ref>{{cite web|title=Health benefits will offset cost of China's climate policy|date=23 April 2018 |url=https://news.mit.edu/2018/study-health-benefits-will-offset-cost-china-climate-policy-0423|publisher=MIT|access-date=15 December 2018}}</ref>

A 2017 study in the ''Economic Journal'' found that for Britain during the period 1851–1860, "a one standard deviation increase in coal use raised infant mortality by 6–8% and that industrial coal use explains roughly one-third of the urban mortality penalty observed during this period."<ref>{{Cite journal|last1=Beach|first1=Brian|last2=Hanlon|first2=W. Walker|title=Coal Smoke and Mortality in an Early Industrial Economy|journal=[[Finance:The Economic Journal|The Economic Journal]] |volume=128|issue=615|language=en|pages=2652–2675|doi=10.1111/ecoj.12522|issn=1468-0297|year=2018|s2cid=7406965}}</ref>

Breathing in coal dust causes coalworker's pneumoconiosis or "black lung", so called because the coal dust literally turns the lungs black.<ref>{{cite web|url=http://www.webmd.com/lung/tc/black-lung-disease-topic-overview|title=Black Lung Disease-Topic Overview|work=WebMD|url-status=live|archive-url=https://web.archive.org/web/20150710021533/http://www.webmd.com/lung/tc/black-lung-disease-topic-overview|archive-date=10 July 2015}}</ref> In the US alone, it is estimated that 1,500 former employees of the coal industry die every year from the effects of breathing in coal mine dust.<ref>{{cite web|url=http://www.umwa.org/?q=content/black-lung|title=Black Lung|work=umwa.org|access-date=7 January 2016|url-status=live|archive-url=https://web.archive.org/web/20160203042713/http://www.umwa.org/?q=content%2Fblack-lung|archive-date=3 February 2016}}</ref>

Huge amounts of coal ash and other waste is produced annually. Use of coal generates hundreds of millions of tons of ash and other waste products every year. These include [[Chemistry:Fly ash|fly ash]], [[Earth:Bottom ash|bottom ash]], and [[Physics:Flue-gas desulfurization|flue-gas desulfurization]] sludge, that contain [[Chemistry:Mercury (element)|mercury]], [[Chemistry:Uranium|uranium]], [[Chemistry:Thorium|thorium]], [[Chemistry:Arsenic|arsenic]], and other [[Chemistry:Heavy metals|heavy metals]], along with non-metals such as [[Chemistry:Selenium|selenium]].<ref>World Coal Association [http://www.worldcoal.org/pages/content/index.asp?PageID=127 "Environmental impact of Coal Use"] {{webarchive|url=https://web.archive.org/web/20090223203113/http://www.worldcoal.org/pages/content/index.asp?PageID=127 |date=23 February 2009 }}</ref>

Around 10% of coal is ash.<ref>{{cite web|archive-url=https://web.archive.org/web/20150720233354/http://www.epa.gov/cleanenergy/energy-and-you/affect/coal.html|archive-date=20 July 2015|url=http://www.epa.gov/cleanenergy/energy-and-you/affect/coal.html|title=Coal|work=U.S. Environmental Protection Agency |date=2014-02-05}}</ref> Coal ash is hazardous and toxic to human beings and some other living things.<ref>{{cite web|url=http://www.psr.org/environment-and-health/code-black/coal-ash-toxic-and-leaking.html|title=Coal Ash: Toxic – and Leaking|work=psr.org|url-status=live|archive-url=https://web.archive.org/web/20150715170100/http://www.psr.org/environment-and-health/code-black/coal-ash-toxic-and-leaking.html|archive-date=15 July 2015}}</ref> Coal ash contains the radioactive elements [[Chemistry:Uranium|uranium]] and [[Chemistry:Thorium|thorium]]. Coal ash and other solid combustion byproducts are stored locally and escape in various ways that expose those living near coal plants to radiation and environmental toxics.<ref name="sa-coal-ash-more-rdactiv">{{cite web|url=http://www.scientificamerican.com/article/coal-ash-is-more-radioactive-than-nuclear-waste|title=Coal Ash Is More Radioactive than Nuclear Waste|author=Hvistendahl, Mara|work=Scientific American|date=13 December 2007|url-status=live|archive-url=https://web.archive.org/web/20150710171812/http://www.scientificamerican.com/article/coal-ash-is-more-radioactive-than-nuclear-waste/|archive-date=10 July 2015}}</ref>

==Damage to the environment==


[[File:Aerial view of ash slide site Dec 23 2008 TVA.gov 123002.jpg|thumb|Aerial photograph of the site of the Kingston Fossil Plant coal fly ash slurry spill taken the day after the event]]

Coal mining, coal combustion wastes and [[Physics:Flue gas|flue gas]] are causing major environmental damage.<ref>{{Cite web |title=Coal and the environment - U.S. Energy Information Administration (EIA) |url=https://www.eia.gov/energyexplained/coal/coal-and-the-environment.php |access-date=2023-01-27 |website=www.eia.gov}}</ref><ref>{{Cite web |last=Zagoruichyk |first=Anastasiia |date=2022-07-06 |title=Emissions from mining cause 'up to £2.5tn' in environmental damages each year |url=https://www.carbonbrief.org/emissions-from-mining-cause-up-to-2-5tn-in-environmental-damages-each-year/ |access-date=2023-01-27 |website=Carbon Brief |language=en}}</ref>

Water systems are affected by coal mining.<ref>{{cite journal|title=Environmental Impact of Coal Mining on Water Regime and Its Management|author=Tiwary, R. K. |journal=Water, Air, & Soil Pollution|year=2001|volume=132|pages=185–99|doi=10.1023/a:1012083519667|bibcode=2001WASP..132..185T |s2cid=91408401 }}</ref> For example, mining affects [[Earth:Groundwater|groundwater]] and [[Earth:Water table|water table]] levels and acidity. Spills of fly ash, such as the Kingston Fossil Plant coal fly ash slurry spill, can also contaminate land and waterways, and destroy homes. Power stations that burn coal also consume large quantities of water. This can affect the flows of rivers, and has consequential impacts on other land uses. In areas of [[Water scarcity|water scarcity]], such as the [[Earth:Thar Desert|Thar Desert]] in {{wipe|Pakistan}}, coal mining and coal power plants contribute to the depletion of water resources.<ref>{{cite news |title=Pakistan's Coal Trap |url=https://www.dawn.com/news/1387151 |work=Dawn |date=4 February 2018}}</ref>

One of the earliest known impacts of coal on the [[Physics:Water cycle|water cycle]] was [[Earth:Acid rain|acid rain]]. In 2014, approximately 100 [[Orders of magnitude (mass)#106 to 1011 kg|Tg]]/S of [[Chemistry:Sulfur dioxide|sulfur dioxide]] (SO<sub>2</sub>) was released, over half of which was from burning coal.<ref>{{Cite journal|last1=Zhong|first1=Qirui|last2=Shen |first2=Huizhong|last3=Yun|first3=Xiao|last4=Chen|first4=Yilin|last5=Ren|first5=Yu’ang|last6=Xu |first6=Haoran|last7=Shen|first7=Guofeng|last8=Du |first8=Wei|last9=Meng|first9=Jing|last10=Li |first10=Wei|last11=Ma|first11=Jianmin|date=2020-06-02|title=Global Sulfur Dioxide Emissions and the Driving Forces|url=https://doi.org/10.1021/acs.est.9b07696|journal=Environmental Science & Technology |volume=54|issue=11|pages=6508–6517|doi=10.1021/acs.est.9b07696|pmid=32379431|bibcode=2020EnST...54.6508Z |s2cid=218556619|issn=0013-936X}}</ref> After release, the sulfur dioxide is oxidized to H<sub>2</sub>SO<sub>4</sub> which scatters solar radiation, hence its increase in the atmosphere exerts a cooling effect on the climate. This beneficially masks some of the warming caused by increased greenhouse gases. However, the sulfur is precipitated out of the atmosphere as acid rain in a matter of weeks,<ref>{{cite journal|title=The oxidation rate and residence time of sulphur dioxide in the arctic atmosphere |author1=Barrie, L.A. |author2=Hoff, R.M. |journal=Atmospheric Environment|volume=18|issue=12|year=1984 |pages=2711–2722|doi=10.1016/0004-6981(84)90337-8|bibcode=1984AtmEn..18.2711B }}</ref> whereas carbon dioxide remains in the atmosphere for hundreds of years. Release of SO<sub>2</sub> also contributes to the widespread acidification of ecosystems.<ref>Human Impacts on Atmospheric Chemistry, by PJ Crutzen and J Lelieveld, Annual Review of Earth and Planetary Sciences, Vol. 29: 17–45 (Volume publication date May 2001)</ref>

Disused coal mines can also cause issues. Subsidence can occur above tunnels, causing damage to infrastructure or cropland. Coal mining can also cause long lasting fires, and it has been estimated that thousands of coal seam fires are burning at any given time.<ref name="Deep underground">{{cite magazine |magazine={{wipe|Time (magazine)}} |date=23 July 2010 |author=Cray, Dan |title=Deep Underground, Miles of Hidden Wildfires Rage |url=http://www.time.com/time/health/article/0,8599,2006195,00.html |archive-url= https://web.archive.org/web/20100728003147/http://www.time.com/time/health/article/0,8599,2006195,00.html |archive-date=28 July 2010 |url-status=dead}}</ref> For example, Brennender Berg has been burning since 1668 and is still burning in the 21st century.<ref name="mineralienatlas">{{cite web |title=Das Naturdenkmal Brennender Berg bei Dudweiler |trans-title=The natural monument Burning Mountain in Dudweiler |language=de |work=Mineralienatlas |access-date=3 October 2016 |url=https://www.mineralienatlas.de/?l=3741}}</ref>

The production of coke from coal produces ammonia, coal tar, and gaseous compounds as byproducts which if discharged to land, air or waterways can pollute the environment.<ref>{{cite web|title=World Of Coke: Coke is a High Temperature Fuel|url=http://www.ustimes.com/WorldOfCoke/|website=www.ustimes.com|access-date=16 January 2016|url-status=live|archive-url=https://web.archive.org/web/20151127154337/http://www.ustimes.com/WorldOfCoke/ |archive-date=27 November 2015}}</ref> The Whyalla steelworks is one example of a coke producing facility where liquid ammonia was discharged to the marine environment.<ref>{{Cite book|last1=Rajaram|first1=Vasudevan |url=https://books.google.com/books?id=5uTM2jFMzH4C&pg=PA113|title=Sustainable Mining Practices: A Global Perspective|last2=Parameswaran|first2=Krishna |last3=Dutta|first3=Subijoy|publisher=CRC Press|year=2005 |isbn=978-1-4398-3423-7|location=|pages=113}}</ref>

===Emission intensity===
[[Earth:Emission intensity|Emission intensity]] is the [[Physics:Life-cycle greenhouse-gas emissions of energy sources|greenhouse gas emitted over the life of a generator]] per unit of electricity generated. The emission intensity of coal power stations is high, as they emit around 1000&nbsp;g of CO<sub>2</sub>eq for each kWh generated, while natural gas is medium-emission intensity at around 500&nbsp;g CO<sub>2</sub>eq per kWh. The emission intensity of coal varies with type and generator technology and exceeds 1200&nbsp;g per kWh in some countries.<ref>{{cite journal |title=Real-Time Carbon Accounting Method for the European Electricity Markets |journal=Energy Strategy Reviews |volume=26 |pages=100367 |arxiv=1812.06679 |last1=Tranberg |first1=Bo |last2=Corradi |first2=Olivier |last3=Lajoie |first3=Bruno |last4=Gibon |first4=Thomas |last5=Staffell |first5=Iain |first6=Gorm Bruun |last6=Andresen |doi=10.1016/j.esr.2019.100367 |year=2019 |s2cid=125361063}}</ref>

===Underground fires===
Thousands of coal fires are burning around the world.<ref>{{cite web|title=Sino German Coal fire project |url=http://www.coalfire.caf.dlr.de/projectareas/world_wide_distribution_en.html |access-date=9 September 2005 |url-status=dead |archive-url=https://web.archive.org/web/20050830091254/http://www.coalfire.caf.dlr.de/projectareas/world_wide_distribution_en.html |archive-date=30 August 2005}}</ref> Those burning underground can be difficult to locate and many cannot be extinguished. Fires can cause the ground above to subside, their combustion gases are dangerous to life, and breaking out to the surface can initiate surface [[Biology:Wildfire|wildfire]]s. Coal seams can be set on fire by [[Physics:Spontaneous combustion|spontaneous combustion]] or contact with a mine fire or surface fire. Lightning strikes are an important source of ignition. The coal continues to burn slowly back into the seam until oxygen (air) can no longer reach the flame front. A grass fire in a coal area can set dozens of coal seams on fire.<ref>{{cite web |title=Committee on Resources-Index |url=http://resourcescommittee.house.gov/archives/108/testimony/johnmasterson.htm |access-date=9 September 2005 |archive-url=https://web.archive.org/web/20050825231038/http://resourcescommittee.house.gov/archives/108/testimony/johnmasterson.htm |archive-date=25 August 2005 |url-status=dead}}</ref><ref>{{cite web |title=Snapshots 2003 |work=fire.blm.gov |url=http://www.fire.blm.gov/textdocuments/6-27-03.pdf |archive-url=https://web.archive.org/web/20060218013724/http://www.fire.blm.gov/textdocuments/6-27-03.pdf |archive-date=18 February 2006 |access-date=9 September 2005 |url-status=dead}}</ref> Coal fires in China burn an estimated 120 million tons of coal a year, emitting 360 million metric tons of CO<sub>2</sub>, amounting to 2–3% of the annual worldwide production of CO<sub>2</sub> from fossil fuels.<ref>{{cite web|title=EHP 110-5, 2002: Forum |url=http://ehp.niehs.nih.gov/docs/2002/110-5/forum.html |access-date=9 September 2005 |url-status=dead |archive-url=https://web.archive.org/web/20050731081620/http://ehp.niehs.nih.gov/docs/2002/110-5/forum.html |archive-date=31 July 2005 }}</ref><ref>{{cite web|title=Overview about ITC's activities in China |url=http://www.itc.nl/personal/coalfire/activities/overview.html |access-date=9 September 2005 |archive-url=https://web.archive.org/web/20050616004903/http://www.itc.nl/personal/coalfire/activities/overview.html |archive-date=16 June 2005 |url-status=dead}}</ref> In Centralia, Pennsylvania (a borough located in the Coal Region of the U.S.), an exposed vein of anthracite ignited in 1962 due to a trash fire in the borough landfill, located in an abandoned [[Chemistry:Anthracite|anthracite]] strip mine pit. Attempts to extinguish the fire were unsuccessful, and it continues to burn underground to this day. The Australian Burning Mountain was originally believed to be a volcano, but the smoke and ash come from a coal fire that has been burning for some 6,000 years.<ref>{{cite web | title=Fire in The Hole | url=http://www.smithsonianmag.com/travel/firehole.html | archive-url=http://arquivo.pt/wayback/20091014102731/http%3A//www.smithsonianmag.com/travel/firehole.html | url-status=dead | archive-date=14 October 2009 | access-date=5 June 2011 }}</ref>

At Kuh i Malik in Yagnob Valley, Tajikistan, coal deposits have been burning for thousands of years, creating vast underground labyrinths full of unique minerals, some of them very beautiful.

The reddish siltstone rock that caps many ridges and buttes in the [[Earth:Powder River Basin|Powder River Basin]] in Wyoming and in western North Dakota is called ''porcelanite'', which resembles the coal burning waste "clinker" or volcanic "[[Earth:Scoria|scoria]]".<ref>{{cite web | title=North Dakota's Clinker | url=http://www.state.nd.us/ndgs/ndnotes/ndn13_h.htm | access-date=9 September 2005 | url-status=live | archive-url=https://web.archive.org/web/20050914120008/http://www.state.nd.us/ndgs/NDNotes/ndn13_h.htm | archive-date=14 September 2005}}</ref> Clinker is rock that has been fused by the natural burning of coal. In the Powder River Basin approximately 27 to 54 billion tons of coal burned within the past three million years.<ref>{{cite web|title=BLM-Environmental Education – The High Plains |url=http://www.blm.gov/education/high_plains/article.html |access-date=9 September 2005 |archive-url=https://web.archive.org/web/20050312133748/http://www.blm.gov/education/high_plains/article.html |archive-date=12 March 2005 |url-status=dead}}</ref> Wild coal fires in the area were reported by the Lewis and Clark Expedition as well as explorers and settlers in the area.<ref>{{cite web|title=Pyrophoricity (spontaneous combustion) of Powder River Basin coals: Considerations for coalbed methane development |url=http://www.wsgs.uwyo.edu/Coal/CR01-1.pdf |access-date=9 September 2005 |archive-url=https://web.archive.org/web/20050912063721/http://www.wsgs.uwyo.edu/Coal/CR01-1.pdf |archive-date=12 September 2005 |author1=Lyman, Robert M. |author2=Volkmer, John E. |date=March 2001|url-status=dead}}</ref>

===Climate change===
[[File:1979- Radiative forcing - climate change - global warming - EPA NOAA.svg|thumb|upright=1.5 | The warming influence (called [[Astronomy:Radiative forcing|radiative forcing]]) of long-lived greenhouse gases has nearly doubled in 40 years, with carbon dioxide being the dominant driver of global warming.<ref name=NOAA_AGGI_2022>{{cite web |title=The NOAA Annual Greenhouse Gas Index (AGGI) |url=https://gml.noaa.gov/aggi/aggi.html |website=NOAA.gov |publisher=National Oceanic and Atmospheric Administration (NOAA) |archive-url=https://web.archive.org/web/20230524133553/https://gml.noaa.gov/aggi/aggi.html |archive-date=24 May 2023 |date=Spring 2023 |url-status=live }}</ref>]]
The largest and most long-term effect of coal use is the release of carbon dioxide, a [[Chemistry:Greenhouse gas|greenhouse gas]] that causes [[Earth:Climate change|climate change]]. Coal-fired power plants were the single largest contributor to the growth in global CO<sub>2</sub> emissions in 2018,<ref name="Gençsü 2019, p. 8">Gençsü (2019), p. 8</ref> 40% of the total fossil fuel emissions,<ref name =phys2018>{{cite web|url=https://phys.org/news/2018-12-china-unbridled-export-coal-power_1.html|title=China's unbridled export of coal power imperils climate goals|access-date=7 December 2018}}</ref> and more than a quarter of total emissions.<ref name="cebf"/>{{refn|14.4 gigatonnes coal/50 gigatonnes total|group=note}} Coal mining can emit methane, another greenhouse gas.<ref>{{cite news |title=China's Coal Plants Haven't Cut Methane Emissions as Required, Study Finds |url=https://www.nytimes.com/2019/01/29/climate/china-coal-climate-change.html |work={{wipe|The New York Times}} |date=29 January 2019}}</ref><ref>{{Cite web|url=https://www.carbonbrief.org/coal-mines-emit-more-methane-than-oil-and-gas-sector-study-finds|title=Coal mines emit more methane than oil-and-gas sector, study finds|last=Gabbatiss|first=Josh|date=2020-03-24|website=Carbon Brief|language=en|access-date=2020-03-29}}</ref>

In 2016 world gross carbon dioxide emissions from coal usage were 14.5 gigatonnes.<ref>{{cite web |title=Emissions |url=http://www.globalcarbonatlas.org/en/CO2-emissions |publisher=Global Carbon Atlas |access-date=6 November 2018}}</ref> For every megawatt-hour generated, coal-fired electric power generation emits around a tonne of carbon dioxide, which is double the approximately 500&nbsp;kg of carbon dioxide released by a [[Chemistry:Natural gas|natural gas]]-fired electric plant.<ref>{{cite web|title=How much carbon dioxide is produced when different fuels are burned?|work=eia.gov|url=https://www.eia.gov/tools/faqs/faq.cfm?id=73&t=11|access-date=7 January 2016|url-status=live|archive-date=12 January 2016|archive-url=https://web.archive.org/web/20160112095655/http://www.eia.gov/tools/faqs/faq.cfm?id=73&t=11}}</ref> In 2013, the head of the UN climate agency advised that most of the world's coal reserves should be left in the ground to avoid catastrophic global warming.<ref>{{cite news|title=Leave coal in the ground to avoid climate catastrophe, UN tells industry|url=https://www.theguardian.com/environment/2013/nov/18/leave-coal-avoid-climate-catastrophe-un|url-status=live|archive-url=https://web.archive.org/web/20170102164315/https://www.theguardian.com/environment/2013/nov/18/leave-coal-avoid-climate-catastrophe-un|archive-date=2 January 2017|newspaper=The Guardian |date=2013-11-18 |last1=Vidal|first1=John|last2=Readfearn|first2=Graham}}</ref> To keep global warming below 1.5&nbsp;°C or 2&nbsp;°C hundreds, or possibly thousands, of coal-fired power plants will need to be retired early.<ref>{{Cite web|url=https://www.nationalgeographic.com/environment/2019/07/we-have-too-many-fossil-fuel-power-plants-to-meet-climate-goals/|archive-url=https://web.archive.org/web/20190702105444/https://www.nationalgeographic.com/environment/2019/07/we-have-too-many-fossil-fuel-power-plants-to-meet-climate-goals/|url-status=dead|archive-date=2 July 2019|title=We have too many fossil-fuel power plants to meet climate goals |date=2019-07-01 |website=Environment|language=en|access-date=2019-09-30}}</ref>

==Pollution mitigation==
{{Excerpt|Coal Pollution Mitigation|only=files|hat=no}}
{{Excerpt|Coal Pollution Mitigation|only=paragraphs}}

===Standards===
Local pollution standards include GB13223-2011 (China), India,<ref>{{cite journal |title=How can Indian power plants cost-effectively meet the new sulfur emission standards? Policy evaluation using marginal abatement cost-curves |journal=Energy Policy|volume=121|pages=124–37|doi=10.1016/j.enpol.2018.06.008|year=2018 |last1=Sugathan |first1=Anish |last2=Bhangale|first2=Ritesh|last3=Kansal|first3=Vishal|last4=Hulke|first4=Unmil|s2cid=158703760}}</ref> the Industrial Emissions Directive (EU) and the Clean Air Act (United States).

===Satellite monitoring===

Satellite monitoring is now used to crosscheck national data, for example Sentinel-5 Precursor has shown that Chinese control of SO<sub>2</sub> has only been partially successful.<ref>{{cite journal |title= Quantifying coal power plant responses to tighter SO<sub>2</sub> emissions standards in China|journal=Proceedings of the National Academy of Sciences|volume=115|issue=27|pages=7004–09|doi=10.1073/pnas.1800605115|pmid=29915085|pmc=6142229|year=2018 |last1=Karplus |first1=Valerie J. |last2=Zhang|first2=Shuang|last3=Almond|first3=Douglas|bibcode=2018PNAS..115.7004K |doi-access=free}}</ref> It has also revealed that low use of technology such as SCR has resulted in high NO<sub>2</sub> emissions in South Africa and India.<ref>{{cite news |title=New satellite data analysis reveals world's biggest NO<sub>2</sub> emissions hotspots |url=https://www.greenpeace.org/international/press-release/19072/greenpeace-analysis-of-new-satellite-data-reveals-worlds-biggest-no2-emissions-hotspots/ |publisher=Greenpeace International}}</ref>

===Combined cycle power plants===
A few [[Physics:Integrated gasification combined cycle|Integrated gasification combined cycle]] (IGCC) coal-fired power plants have been built with [[Chemistry:Coal gasification|coal gasification]]. Although they burn coal more efficiently and therefore emit less pollution, the technology has not generally proved economically viable for coal, except possibly in Japan although this is controversial.<ref>{{cite web |title=Universal failure: How IGCC coal plants waste money and emissions Nove |url=http://www.kikonet.org/wp/wp-content/uploads/2016/11/IGCC-and-emissions_eg_final.pdf |archive-url=https://web.archive.org/web/20161219175414/http://www.kikonet.org/wp/wp-content/uploads/2016/11/IGCC-and-emissions_eg_final.pdf |archive-date=2016-12-19 |url-status=live |publisher=Kiko Network |access-date=13 November 2018}}</ref><ref>{{cite news |title=Japan says no to high-emission coal power plants |url=https://asia.nikkei.com/Politics/Japan-says-no-to-high-emission-coal-power-plants |work=Nikkei Asian Review |date=26 July 2018}}</ref>

===Carbon capture and storage===

Although still being intensively researched and considered economically viable for some uses other than with coal; [[Physics:Carbon capture and storage|carbon capture and storage]] has been tested at the [[Engineering:Petra Nova|Petra Nova]] and [[Engineering:Boundary Dam Power Station|Boundary Dam]] coal-fired power plants and has been found to be technically feasible but not economically viable for use with coal, due to reductions in the cost of solar PV technology.<ref>{{cite journal |title=Coal with Carbon Capture and Sequestration is not as Land Use Efficient as Solar Photovoltaic Technology for Climate Neutral Electricity Production |journal=Nature |volume=8 |issue=1 |pages=13476 |doi=10.1038/s41598-018-31505-3 |pmid=30194324 |pmc=6128891 |bibcode=2018NatSR...813476G |year=2018 |last1=Groesbeck |first1=James Gunnar |last2=Pearce |first2=Joshua M. }}</ref>

==Economics==
In 2018 {{USD| 80 billion}} was invested in coal supply but almost all for sustaining production levels rather than opening new mines.<ref>{{Cite web|url=https://webstore.iea.org/login?ReturnUrl=%2fdownload%2fdirect%2f2738%3ffileName%3dWEI2019.pdf&fileName=WEI2019.pdf|title=World Energy Investment 2019|website=webstore.iea.org|access-date=2019-07-14|archive-date=22 June 2020|archive-url=https://web.archive.org/web/20200622140004/https://webstore.iea.org/login?ReturnUrl=%2Fdownload%2Fdirect%2F2738%3FfileName%3DWEI2019.pdf&fileName=WEI2019.pdf|url-status=dead}}</ref>
In the long term coal and oil could cost the world trillions of dollars per year.<ref>{{Cite news|url=https://www.theguardian.com/environment/2018/dec/10/tackle-climate-or-face-financial-crash-say-worlds-biggest-investors |title=Tackle climate or face financial crash, say world's biggest investors|last=Carrington|first=Damian|date=2018-12-10|work=The Guardian|access-date=2019-07-22|language=en-GB|issn=0261-3077}}</ref><ref>{{Cite journal |last1=Kompas|first1=Tom|last2=Pham|first2=Van Ha|last3=Che|first3=Tuong Nhu|date=2018|title=The Effects of Climate Change on GDP by Country and the Global Economic Gains From Complying With the Paris Climate Accord|journal=Earth's Future|language=en|volume=6|issue=8|pages=1153–1173|doi=10.1029/2018EF000922|bibcode=2018EaFut...6.1153K|issn=2328-4277|doi-access=free|hdl=1885/265534|hdl-access=free}}</ref> Coal alone may cost Australia billions,<ref>{{cite news |title=Labor opposes plan to indemnify new coal plants and warns it could cost billions |url=https://www.theguardian.com/environment/2018/oct/24/labor-opposes-plan-to-indemnify-new-coal-plants-warns-it-could-cost-billions |work=The Guardian |date=24 October 2018}}</ref> whereas costs to some smaller companies or cities could be on the scale of millions of dollars.<ref>{{cite news |title=Superfund Scandal Leads to Prison Time for Coal Lobbyist, Lawyer |url=https://www.sierraclub.org/sierra/birmingham-superfund-scandal-leads-prison-time-for-coal-lobbyist-lawyer-drummond |publisher=Sierra Club |date=24 October 2018}}</ref> The economies most damaged by coal (via climate change) may be India and the US as they are the countries with the highest [[Earth:Social cost of carbon|social cost of carbon]].<ref>{{cite journal |title=Country-level social cost of carbon |journal=Nature Climate Change |volume=8 |issue=10 |pages=895–900 |doi=10.1038/s41558-018-0282-y |bibcode=2018NatCC...8..895R |year=2018 |last1=Ricke |first1=Katharine |last2=Drouet |first2=Laurent |last3=Caldeira |first3=Ken |last4=Tavoni |first4=Massimo |hdl=11311/1099986 |s2cid=135079412 |hdl-access=free }}</ref> Bank loans to finance coal are a risk to the Indian economy.<ref name=Economist2018/>

China is the largest producer of coal in the world. It is the world's largest energy consumer, and coal in China supplies 60% of its primary energy. However two fifths of China's coal power stations are estimated to be loss-making.<ref name="CarbTrk2018" />

Air pollution from coal storage and handling costs the US almost 200 dollars for every extra ton stored, due to PM2.5.<ref>{{cite journal |title=The local air pollution cost of coal storage and handling: Evidence from U.S. power plants |journal=Journal of Environmental Economics and Management|volume=92|pages=360–396 |doi=10.1016/j.jeem.2018.09.005|year=2018|last1=Jha|first1=Akshaya|last2=Muller|first2=Nicholas Z. |s2cid=158803149}}</ref> Coal pollution costs the {{€|43 billion}} each year.<ref>{{cite magazine |title=The human cost of coal in the UK: 1600 deaths a year|magazine=New Scientist |url=https://www.newscientist.com/article/mg22029461.800-the-human-cost-of-coal-in-the-uk-1600-deaths-a-year.html|url-status=live|archive-url=https://web.archive.org/web/20150424025154/http://www.newscientist.com/article/mg22029461.800-the-human-cost-of-coal-in-the-uk-1600-deaths-a-year.html|archive-date=24 April 2015}}</ref> Measures to cut air pollution benefit individuals financially and the economies of countries<ref>{{cite news|url=https://www.economist.com/blogs/freeexchange/2014/02/environmentalism|title=Environmentalism|date=4 February 2014|newspaper=The Economist|access-date=7 January 2016|url-status=live|archive-url=https://web.archive.org/web/20160128191945/http://www.economist.com/blogs/freeexchange/2014/02/environmentalism|archive-date=28 January 2016}}</ref><ref>{{cite web |title=Air Pollution and Health in Bulgaria |url=http://env-health.org/IMG/pdf/heal_briefing_air_bulgaria_eng.pdf |archive-url=https://web.archive.org/web/20151227144303/http://env-health.org/IMG/pdf/heal_briefing_air_bulgaria_eng.pdf |archive-date=2015-12-27 |url-status=live |publisher=HEAL |access-date=26 October 2018}}</ref> such as China.<ref>{{cite journal |title=Health-related benefits of air quality improvement from coal control in China: Evidence from the Jing-Jin-Ji region |journal=Resources, Conservation and Recycling|volume=129|pages=416–423|doi=10.1016/j.resconrec.2016.09.021 |year=2018|last1=Sun|first1=Dong|last2=Fang|first2=Jing|last3=Sun|first3=Jingqi}}</ref>

===Subsidies===
Subsidies for coal in 2021 have been estimated at {{US$|19 billion}}, not including electricity subsidies, and are expected to rise in 2022.<ref>{{Cite web |title=Support for fossil fuels almost doubled in 2021, slowing progress toward international climate goals, according to new analysis from OECD and IEA - OECD |url=https://www.oecd.org/newsroom/support-for-fossil-fuels-almost-doubled-in-2021-slowing-progress-toward-international-climate-goals-according-to-new-analysis-from-oecd-and-iea.htm |access-date=2022-09-27 |website=www.oecd.org}}</ref> {{As of|2019}} [[Organization:G20|G20]] countries provide at least {{US$|63.9 billion}}<ref name="Gençsü 2019, p. 8"/> of government support per year for the production of coal, including coal-fired power: many subsidies are impossible to quantify<ref name=ClimateTransparency2019>{{Cite web|url=https://www.climate-transparency.org/wp-content/uploads/2019/05/Managing-the-phase-out-of-coal-DIGITAL.pdf |archive-url=https://web.archive.org/web/20190524071757/https://www.climate-transparency.org/wp-content/uploads/2019/05/Managing-the-phase-out-of-coal-DIGITAL.pdf |archive-date=2019-05-24 |url-status=live|title=MANAGING THE PHASE-OUT OF COAL A COMPARISON OF ACTIONS IN G20 COUNTRIES|date=May 2019|website=Climate Transparency}}</ref> but they include {{US$|27.6 billion}} in domestic and international public finance, {{US$|15.4 billion}} in fiscal support, and {{US$|20.9 billion}} in state-owned enterprise (SOE) investments per year.<ref name="Gençsü 2019, p. 8"/> In the EU state aid to new coal-fired plants is banned from 2020, and to existing coal-fired plants from 2025.<ref>{{cite news |title=Deal reached on EU energy market design, incl end of coal subsidies License: CC0 Creative Commons |url=https://renewablesnow.com/news/deal-reached-on-eu-energy-market-design-incl-end-of-coal-subsidies-637143/ |publisher=Renewables Now |date=19 December 2018}}</ref> As of 2018, government funding for new coal power plants was supplied by Exim Bank of China,<ref name="Urgewald 2018">{{cite web |title=Regional Briefings for the 2018 Coal Plant Developers List |url=https://coalexit.org/sites/default/files/inline-files/Regional%20Briefings%20CPDL_10-04-2018_final.pdf |publisher=Urgewald |access-date=27 November 2018}}</ref> the Japan Bank for International Cooperation and Indian public sector banks.<ref>{{cite news |title=The World Needs to Quit Coal. Why Is It So Hard? |url=https://www.nytimes.com/2018/11/24/climate/coal-global-warming.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2018/11/24/climate/coal-global-warming.html |archive-date=2022-01-01 |url-access=limited |work={{wipe|The New York Times}} |date=24 November 2018}}{{cbignore}}</ref> Coal in Kazakhstan was the main recipient of coal consumption subsidies totalling US$2 billion in 2017.<ref>{{cite web |title=Fossil-fuel subsidies|url=https://www.iea.org/weo/energysubsidies/ |publisher=[[Organization:International Energy Agency|IEA]] |access-date=16 November 2018}}</ref> Coal in Turkey benefited from substantial subsidies in 2021.<ref>{{Cite web|title=Turkey|url=https://ember-climate.org/global-electricity-review-2021/g20-profiles/turkey/|access-date=2021-10-09|website=Ember|date=28 March 2021 |language=en-GB}}</ref>

===Stranded assets===
Some coal-fired power stations could become stranded assets, for example China Energy Investment, the world's largest power company, risks losing half its capital.<ref name="CarbTrk2018" /> However, state-owned electricity utilities such as Eskom in South Africa, Perusahaan Listrik Negara in Indonesia, Sarawak Energy in Malaysia, Taipower in Taiwan, EGAT in Thailand, Vietnam Electricity and EÜAŞ in Turkey are building or planning new plants.<ref name="Urgewald 2018b">{{cite web|title=Regional Briefings for the 2018 Coal Plant Developers List|url=https://coalexit.org/sites/default/files/inline-files/Regional%20Briefings%20CPDL_10-04-2018_final.pdf |access-date=27 November 2018|publisher=Urgewald}}</ref> As of 2021 this may be helping to cause a [[Finance:Carbon bubble|carbon bubble]] which could cause financial instability if it bursts.<ref>{{Cite web |url=https://cosmosmagazine.com/climate/stranded-fossil-fuel-assets-may-prompt-4-trillion-crisis|title='Stranded' fossil fuel assets may prompt {{US$|long=no|4 trillion}} crisis|website=Cosmos |date=4 June 2018 |access-date=2019-09-30}}</ref><ref>{{Cite web|last=Carrington|first=Damian|date=2021-09-08|title=How much of the world's oil needs to stay in the ground?|url=https://www.theguardian.com/environment/2021/sep/08/climate-crisis-fossil-fuels-ground|url-status=live|access-date=2021-09-10|website=The Guardian|language=en |archive-date=8 September 2021 |archive-url=https://web.archive.org/web/20210908153408/https://www.theguardian.com/environment/2021/sep/08/climate-crisis-fossil-fuels-ground}}</ref><ref>{{Cite journal|last1=Welsby|first1=Dan|last2=Price|first2=James |last3=Pye |first3=Steve|last4=Ekins|first4=Paul|date=2021-09-08|title=Unextractable fossil fuels in a 1.5 °C world|journal=Nature|language=en|volume=597|issue=7875|pages=230–234|doi=10.1038/s41586-021-03821-8 |pmid=34497394 |bibcode=2021Natur.597..230W|issn=1476-4687|doi-access=free}}</ref>

==Politics==
Countries building or financing new coal-fired power stations, such as China, India, Indonesia, Vietnam, Turkey and Bangladesh, face mounting international criticism for obstructing the aims of the Paris Agreement.<ref name="Cornot-Gandolfe 2018" /><ref>{{Cite web|url=https://www.spglobal.com/marketintelligence/en/news-insights/latest-news-headlines/5-asian-countries-building-80-of-new-coal-power-carbon-tracker-65232956|title = 5 Asian countries building 80% of new coal power – Carbon Tracker}}</ref><ref>{{Cite web|url=https://electrek.co/2021/09/14/egeb-76-of-proposed-coal-plants-have-been-canceled-since-2015/|title=EGEB: 76% of proposed coal plants have been canceled since 2015|date=14 September 2021}}</ref>  In 2019, the Pacific Island nations (in particular Vanuatu and Fiji) criticized Australia for failing to cut their emissions at a faster rate than they were, citing concerns about coastal inundation and erosion.<ref name=Guardian2018/> In May 2021, the G7 members agreed to end new direct government support for international coal power generation.<ref>{{Cite web|last=Fiona|first=Harvey|date=2021-05-21|title=Richest nations agree to end support for coal production overseas|url=http://www.theguardian.com/environment/2021/may/21/richest-nations-agree-to-end-support-for-coal-production-overseas|access-date=2021-05-22|website=The Guardian|language=en}}</ref>
[[File:Coral not coal protest at India Finance Minister Arun Jaitley Visit to Australia (25563929593).jpg| right|thumb|Protesting against damage to the Great Barrier Reef caused by climate change in Australia]]
Opposition to coal pollution was one of the main reasons the modern environmental movement started in the 19th century. {{Citation needed|date=March 2023}}

==Transition away from coal==
{{multiple image | total_width=450
| image1=2000- Retired coal-fired power capacity - Global Energy Monitor.svg |caption1= The annual amount of coal plant capacity being retired increased into the mid-2010s.<ref name=GlobalEnergyMonitor_RetiredCoal_2023/> However, the rate of retirement has since stalled,<ref name=GlobalEnergyMonitor_RetiredCoal_2023>{{cite web |title=Retired Coal-fired Power Capacity by Country / Global Coal Plant Tracker |url=https://docs.google.com/spreadsheets/d/1t3gO35bzcVI8ekq9318jBUq6nd7UADcut4gY3vjHZMM/edit#gid=1751753356 |publisher=Global Energy Monitor |archive-url=https://web.archive.org/web/20230409194508/https://docs.google.com/spreadsheets/d/1t3gO35bzcVI8ekq9318jBUq6nd7UADcut4gY3vjHZMM/edit#gid=1751753356 |archive-date=9 April 2023 |date=2023 |url-status=live }} — Global Energy Monitor's [https://globalenergymonitor.org/projects/global-coal-plant-tracker/summary-tables/ Summary of Tables] ([https://web.archive.org/web/20230408201908/https://globalenergymonitor.org/projects/global-coal-plant-tracker/summary-tables/ archive])</ref> and global coal phase-out is not yet compatible with the goals of the Paris Climate Agreement.<ref name=GlobalEnergyMonitor20230405>{{cite web|title=Boom and Bust Coal / Tracking the Global Coal Plant Pipeline |url=https://globalenergymonitor.org/wp-content/uploads/2023/03/Boom-Bust-Coal-2023.pdf |page=3 |publisher=Global Energy Monitor |archive-url=https://web.archive.org/web/20230407125552/https://globalenergymonitor.org/wp-content/uploads/2023/03/Boom-Bust-Coal-2023.pdf |archive-date=7 April 2023 |date=5 April 2023 |url-status=live}}</ref>
| image2= 2000- New coal-fired power capacity - Global Energy Monitor.svg |caption2= In parallel with retirement of some coal plant capacity, other coal plants are still being added, though the annual amount of added capacity has been declining since the 2010s.<ref>{{cite web |title=New Coal-fired Power Capacity by Country / Global Coal Plant Tracker |url=https://docs.google.com/spreadsheets/d/1j35F0WrRJ9dbIJhtRkm8fvPw0Vsf-JV6G95u7gT-DDw/edit#gid=647531100 |publisher=Global Energy Monitor |archive-url=https://web.archive.org/web/20230319120539/https://docs.google.com/spreadsheets/d/1j35F0WrRJ9dbIJhtRkm8fvPw0Vsf-JV6G95u7gT-DDw/edit#gid=647531100 |archive-date=19 March 2023 |date=2023 |url-status=live}} — Global Energy Monitor's [https://globalenergymonitor.org/projects/global-coal-plant-tracker/summary-tables/ Summary of Tables] ([https://web.archive.org/web/20230408201908/https://globalenergymonitor.org/projects/global-coal-plant-tracker/summary-tables/ archive])</ref>
}}
In order to meet global climate goals and provide power to those that do not currently have it coal power must be reduced from nearly 10,000&nbsp;TWh to less than 2,000&nbsp;TWh by 2040.<ref>{{cite news |title=Coal dumped as IEA turns to wind and solar to solve climate challenge |url=https://reneweconomy.com.au/coal-dumped-as-iea-turns-to-wind-and-solar-to-solve-climate-challenge-66916/ |work=Renew Economy |date=13 November 2018}}</ref> Phasing out coal has short-term health and environmental benefits which exceed the costs,<ref>{{Cite web|url=https://www.pik-potsdam.de/news/press-releases/coal-exit-benefits-outweigh-its-costs|title=Coal exit benefits outweigh its costs — PIK Research Portal|website=www.pik-potsdam.de|access-date=2020-03-24|archive-date=24 March 2020|archive-url=https://web.archive.org/web/20200324183652/https://www.pik-potsdam.de/news/press-releases/coal-exit-benefits-outweigh-its-costs|url-status=dead}}</ref> but some countries still favor coal,<ref>{{cite news |title=In coal we trust: Australian voters back PM Morrison's faith in fossil fuel |url=https://uk.reuters.com/article/us-australia-election-energy/in-coal-we-trust-australian-voters-back-pm-morrisons-faith-in-fossil-fuel-idUKKCN1SP06F |work=Reuters |date=19 May 2019}}</ref> and there is much disagreement about how quickly it should be phased out.<ref>{{cite journal | last1 = Rockström | first1 = Johan |  display-authors = etal | year = 2017| title = A roadmap for rapid decarbonization | url = http://pure.iiasa.ac.at/id/eprint/14498/1/Rockstr%C3%B6mEtAl_2017_Science_A%20roadmap%20for%20rapid%20decarbonization.pdf| journal = Science | volume =  355| issue = 6331| pages =  1269–1271| doi = 10.1126/science.aah3443 | bibcode = 2017Sci...355.1269R | pmid = 28336628 | s2cid = 36453591 }}</ref><ref>{{cite news |title=Time for China to Stop Bankrolling Coal |url=https://thediplomat.com/2019/04/time-for-china-to-stop-bankrolling-coal/ |work=The Diplomat |date=29 April 2019}}</ref> However many countries, such as the [[Organization:Powering Past Coal Alliance|Powering Past Coal Alliance]], have already or are transitioned away from coal;<ref>{{cite book |last1=Sartor |first1=O. |title=Implementing Coal Transitions Insights from Case Studies of Major Coal-Consuming Economies |date=2018 |publisher=IDDRI and Climate Strategies |url=https://www.iddri.org/en/publications-and-events/report/implementing-coal-transition-insights-case-studies-major-coal }}</ref> the largest transition announced so far being Germany, which is due to shut down its last coal-fired power station between 2035 and 2038.<ref>{{cite news |title=Germany agrees to end reliance on coal stations by 2038 |url=https://www.theguardian.com/world/2019/jan/26/germany-agrees-to-end-reliance-on-coal-stations-by-2038 |work={{wipe|The Guardian}} |date=26 January 2019}}</ref> Some countries use the ideas of a "Just Transition", for example to use some of the benefits of transition to provide early pensions for coal miners.<ref>{{cite news |title=Spain to close most coalmines in €250m transition deal |url=https://www.theguardian.com/environment/2018/oct/26/spain-to-close-most-coal-mines-after-striking-250m-deal |work={{wipe|The Guardian}} |date=26 October 2018}}</ref> However, low-lying Pacific Islands are concerned the transition is not fast enough and that they will be inundated by [[Earth:Sea level rise|sea level rise]], so they have called for [[Organization:OECD|OECD]] countries to completely phase out coal by 2030 and other countries by 2040.<ref name=Guardian2018>{{cite news |title=Pacific nations under climate threat urge Australia to abandon coal within 12 years |url=https://www.theguardian.com/environment/2018/dec/14/pacific-nations-under-climate-threat-urge-australia-to-abandon-coal-within-12-years |work={{wipe|The Guardian}} |date=13 December 2018}}</ref> In 2020, although China built some plants, globally more coal power was retired than built: the UN Secretary General has also said that OECD countries should stop generating electricity from coal by 2030 and the rest of the world by 2040.<ref>{{Cite magazine|date=2020-12-03|title=The dirtiest fossil fuel is on the back foot|magazine=[[Finance:The Economist|The Economist]]|url=https://www.economist.com/briefing/2020/12/03/the-dirtiest-fossil-fuel-is-on-the-back-foot|issn=0013-0613}}</ref> Phasing down coal was agreed at COP26 in the Glasgow Climate Pact. Vietnam is among few coal-dependent developing countries that pledged to phase out unabated coal power by the 2040s or as early as possible thereafter<ref>{{cite journal |last1=Do |first1=Thang Nam |last2=Burke |first2=J Paul |title=Phasing out coal power in a developing country context: Insights from Vietnam |journal=Energy Policy |year=2023 |volume=176 |issue=May 2023 113512 |page=113512 |doi=10.1016/j.enpol.2023.113512|s2cid=257356936 |hdl=1885/286612 |hdl-access=free }}</ref>

===Peak coal===
[[File:Coal mine Wyoming.jpg|thumb|A coal mine in Wyoming, US. The US has the world's largest coal reserves.]]{{Excerpt|Peak coal}}

===Switch to cleaner fuels and lower carbon electricity generation===

Coal-fired generation puts out about twice as much carbon dioxide—around a tonne for every megawatt hour generated—as electricity generated by burning natural gas at 500&nbsp;kg of [[Chemistry:Greenhouse gas|greenhouse gas]] per megawatt hour.<ref>{{cite web |title=Electricity emissions around the world |date=23 April 2013 |url=http://shrinkthatfootprint.com/electricity-emissions-around-the-world |access-date=30 October 2018}}</ref> In addition to generating electricity, natural gas is also popular in some countries for heating and as an automotive fuel.

The use of coal in the United Kingdom declined as a result of the development of North Sea oil and the subsequent dash for gas during the 1990s. In Canada some [[Physics:Thermal power station|coal power plants]], such as the Hearn Generating Station, switched from coal to natural gas. In 2017, coal power in the US provided 30% of the electricity, down from approximately 49% in 2008,<ref>{{cite web |url=https://www.eia.gov/tools/faqs/faq.php?id=427&t=3 |publisher=U.S. Energy Information Administration |title=Frequently Asked Questions |date=April 18, 2017 |access-date=May 25, 2017 |url-status=live |archive-date=22 May 2017 |archive-url=https://web.archive.org/web/20170522065928/https://www.eia.gov/tools/faqs/faq.php?id=427&t=3}}</ref><ref name=NYTKentucky>{{cite news|author=Lipton, Eric|title=Even in Coal Country, the Fight for an Industry |url=https://www.nytimes.com/2012/05/30/business/energy-environment/even-in-kentucky-coal-industry-is-under-siege.html|access-date=30 May 2012|newspaper=The New York Times|date=29 May 2012|url-status=live |archive-url=https://web.archive.org/web/20120530100528/http://www.nytimes.com/2012/05/30/business/energy-environment/even-in-kentucky-coal-industry-is-under-siege.html|archive-date=30 May 2012}}</ref><ref>{{cite web |url=http://www.eia.doe.gov/cneaf/electricity/epa/figes1.html|title=Figure ES 1. U.S. Electric Power Industry Net Generation|work=Electric Power Annual with data for 2008|publisher=U.S. Energy Information Administration|date=21 January 2010|access-date=7 November 2010}}</ref> due to plentiful supplies of low cost natural gas obtained by hydraulic fracturing of tight shale formations.<ref>[http://www.iea.org/publications/freepublications/publication/KeyWorld2014.pdf] {{Webarchive|url=https://web.archive.org/web/20150405035039/http://www.iea.org/publications/freepublications/publication/keyworld2014.pdf|archive-url=https://web.archive.org/web/20141021020232/http://www.iea.org/publications/freepublications/publication/KeyWorld2014.pdf|archive-date=2014-10-21|url-status=live|date=5 April 2015}} 2012 data p. 24</ref>

===Coal regions in transition===
Some coal-mining regions are highly dependent on coal.<ref>{{Cite web|url=https://ec.europa.eu/energy/topics/oil-gas-and-coal/EU-coal-regions/coal-regions-transition_en|title=Coal regions in transition|last=fernbas|date=2019-08-29|website=Energy - European Commission|language=en|access-date=2020-04-01}}</ref>

===Employment===
Some coal miners are concerned their jobs may be lost in the transition.<ref>{{cite news |title=Thousands protest German coal phaseout |url=https://www.dw.com/en/thousands-protest-german-coal-phaseout/a-46019342 |date=24 October 2018}}</ref> A just transition from coal is supported by the [[Organization:European Bank for Reconstruction and Development|European Bank for Reconstruction and Development]].<ref>{{Cite web|title=The EBRD's just transition initiative|url=https://www.ebrd.com/what-we-do/just-transition-initiative|website=[[Organization:European Bank for Reconstruction and Development|European Bank for Reconstruction and Development]]}}</ref>

===Bioremediation===

The white rot fungus ''[[Biology:Trametes versicolor|Trametes versicolor]]'' can grow on and metabolize naturally occurring coal.<ref>{{cite report |url=http://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/33_4_LOS%20ANGELES_09-88_0514.pdf |title=Biodegradation of coal-related model compounds |author1=Campbell, J.A. |author2=Stewart, D.L. |author3=McCulloch, M. |author4=Lucke, R.B. |author5=Bean, R.M. |pages=514–21 |publisher=Pacific Northwest Laboratory |url-status=dead |archive-url=https://web.archive.org/web/20170102164058/http://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/33_4_LOS%20ANGELES_09-88_0514.pdf |archive-date=2 January 2017}}</ref> The bacteria [[Biology:Diplococcus|Diplococcus]] has been found to degrade coal, raising its temperature.<ref>{{cite journal |author=Potter, M.C. |date=May 1908 |title=Bacteria as agents in the oxidation of amorphous carbon |journal=Proceedings of the Royal Society of London B |volume=80 |issue=539 |pages=239–59 |doi=10.1098/rspb.1908.0023 |doi-access=free}}</ref>

==Cultural usage==
Coal is the official state mineral of Kentucky,<ref>{{cite web|url=http://sos.ky.gov/kids/all/symbols/mineral.htm |title=Kentucky: Secretary of State – State Mineral |date=20 October 2009 |access-date=7 August 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110527221124/http://www.sos.ky.gov/kids/all/symbols/mineral.htm |archive-date=27 May 2011 }}</ref> and the official state rock of Utah<ref>{{cite web|title=Utah State Rock – Coal |url=http://pioneer.utah.gov/research/utah_symbols/rock.html|work=Pioneer: Utah's Online Library |publisher=Utah State Library Division|access-date=7 August 2011|url-status=live|archive-url=https://web.archive.org/web/20111002183417/http://pioneer.utah.gov/research/utah_symbols/rock.html |archive-date=2 October 2011}}</ref> and West Virginia.<ref>{{Cite web |title=WVGES Frequently Asked Questions |url=https://www.wvgs.wvnet.edu/www/faq/faq.htm |access-date=2023-09-25 |website=www.wvgs.wvnet.edu |language=en}}</ref> These US states have a historic link to coal mining.

Some cultures hold that children who misbehave will receive only a lump of coal from Santa Claus for Christmas in their stockings instead of presents.

It is also customary and considered lucky in Scotland and the North of England to give coal as a gift on New Year's Day. This occurs as part of first-footing and represents warmth for the year to come.

==See also==
{{Div col|colwidth=25em}}
* {{annotated link|Earth:Biochar}}
* {{annotated link|Chemistry:Carbochemistry}}
* {{annotated link|Chemistry:Coal analysis}}
* {{annotated link|Earth:Coal measures}} (stratigraphic unit)
* {{annotated link|Physics:Fluidized bed combustion}}
* {{annotated link|Earth:Fossil fuel phase-out}}
* {{annotated link|Finance:The Coal Question|''The Coal Question''}}
* {{annotated link|Earth:Tonstein}}
* {{annotated link|Organization:World Coal Association}}
{{div col end}}

== Notes ==
{{Reflist|group="note"}}
{{notelist}}

==References==
{{Reflist}}

===Sources===
*{{cite web
 |last=Gençsü
 |first=Ipek
 |date=June 2019
 |title=G20 coal subsidies
 |work=Overseas Development Institute
 |url=https://www.odi.org/sites/odi.org.uk/files/resource-documents/12744.pdf
 |access-date=26 June 2019
 |archive-date=31 August 2020
 |archive-url=https://web.archive.org/web/20200831162058/https://www.odi.org/sites/odi.org.uk/files/resource-documents/12744.pdf
 |url-status=dead
 }}

==Further reading==
* {{cite book|last = Freese|first = Barbara|title = Coal: A Human History|year = 2003|publisher = Penguin Books|isbn = 978-0-7382-0400-0|oclc = 51449422|url = https://archive.org/details/coalhumanhistory00free_0}}
* {{cite book |last= Thurber |first=Mark |year=2019 |title=Coal |publisher=Polity Press |isbn=978-1509514014}}
* {{cite book |last1=Paxman |first1=Jeremy |title=Black Gold : The History of How Coal Made Britain. |date=2022 |publisher=William Collins |isbn=9780008128364}}

==External links==
{{Commons|Coal}}
* [https://coaltransitions.org/ Coal Transitions]
* [https://www.worldcoal.org/ World Coal Association]
* [https://www.iea.org/fuels-and-technologies/coal Coal – International Energy Agency]
* [http://www.coalonline.org/site/coalonline/content/home Coal Online – International Energy Agency] {{Webarchive|url=https://web.archive.org/web/20080119164838/http://www.coalonline.org/site/coalonline/content/home |date=19 January 2008 }}
* [https://coalexit.org/ CoalExit]
* [https://euracoal.eu/ European Association for Coal and Lignite]
* [http://www.worldcoal.com/ Coal news and industry magazine]
* [https://globalenergymonitor.org/projects/global-coal-plant-tracker/ Global Coal Plant Tracker]
* [https://energyandcleanair.org/ Centre for Research on Energy and Clean Air]
* {{cite NIE|wstitle=Coal|short=1}}
* {{cite Collier's|wstitle=Coal|short=1}}

{{electricity generation}}

[[Category:Economic geology]]
[[Category:Sedimentary rocks]]
[[Category:Solid fuels]]

{{Sourceattribution|Coal}}