Table Of Content1.12 Fossil Fuels
Ilhami Yildiz, Dalhousie University,Halifax, NS,Canada
r2018ElsevierInc.Allrightsreserved.
1.12.1 Introduction 521
1.12.1.1 Global EnergySource andDemand 522
1.12.1.2 FossilFuel 522
1.12.1.3 Hubbert PeakTheory 524
1.12.2 Oil 526
1.12.2.1 Sources ofOil 526
1.12.2.1.1 Conventional sources 526
1.12.2.1.2 Unconventional sources 526
1.12.2.2 OilReserves 527
1.12.2.2.1 Reservesof unconventional oil 528
1.12.2.3 OilProduction, Demand andTrade 530
1.12.2.4 Peak Oil 534
1.12.2.5 Environmental Impactsof Oil 535
1.12.2.5.1 Case Study:Oil sandsproduction inAlberta, Canada 536
1.12.3 NaturalGas 536
1.12.3.1 Sources ofNatural Gas 537
1.12.3.2 Natural Gas Reserves 537
1.12.3.3 Natural Gas Production,Demand,andTrade 539
1.12.3.4 Peak Gas 542
1.12.3.5 Environmental Impactsof Natural Gas 544
1.12.4 Coal 545
1.12.4.1 Sources ofCoal 545
1.12.4.2 Coal Reserves 546
1.12.4.3 Coal Production,Demand, andTrade 547
1.12.4.4 Peak Coal 550
1.12.4.5 Environmental Impactsof Coal 551
1.12.4.5.1 Case Study:coalmining in China 552
1.12.5 Further CaseStudies 552
1.12.5.1 Case Study:Global FossilFuel Consumption andSupply 552
1.12.5.2 Case Study:Fossil FuelConsumption andSupplyin Africa 553
1.12.5.3 Case Study:Fossil FuelConsumption andSupplyin NorthAmerica 553
1.12.5.4 Case Study:Fossil FuelConsumption andSupplyin theUnites States 553
1.12.5.5 Case Study:Fossil FuelConsumption andSupplyin Brazil 554
1.12.5.6 Case Study:Fossil FuelConsumption andSupplyin theEuropean Union 555
1.12.5.7 Case Study:Fossil FuelConsumption andSupplyin theMiddle East 555
1.12.5.8 Case Study:Fossil FuelConsumption andSupplyin RussianFederation 556
1.12.5.9 Case Study:Fossil FuelConsumption andSupplyin India 557
1.12.5.10 Case Study:Fossil FuelConsumption andSupplyin OtherEmerging Asia 558
1.12.6 Future Prospects 558
1.12.6.1 Oil 558
1.12.6.2 Natural Gas 559
1.12.6.3 Coal 560
1.12.7 ConcludingRemarks 561
1.12.7.1 Oil 561
1.12.7.2 Natural Gas 562
1.12.7.3 Coal 562
References 563
Further Reading 567
RelevantWebsites 567
ComprehensiveEnergySystems,Volume1 doi:10.1016/B978-0-12-809597-3.00111-5 521
522 Fossil Fuels
1.12.1 Introduction
Fossil fuelshave always hadthe majorshare in the global primary energyconsumption.Even though the share of fossil fuel
consumptionhasdecreasedinrecentyearsandispredictedtodecreasefurther,theywillcontinuetoholdthemajorshareinthe
primaryenergymixintheforeseeablefutureasmoreunconventionalfossilfuelsareexplored.Overallfossilfuelconsumption
increasedapproximately51%intheperiodof1995–2015,anditispredictedthattheconsumptionwillincreaseapproximately
18%moreintheperiodof2015–35.Thefollowingsectionsofthischapteroverviewthepast,current,andfuturedevelopments
of fossil fuels, including oil, natural gas, and coal with their reserves, productions, consumptions, peaks and environmental
impacts.
1.12.1.1 GlobalEnergySource andDemand
EnergysupportsallformsoflifeonEarth,andisdirectlyacquiredfromsunlightbyphotosyntheticorganisms,includingplantsand
microorganisms.Thisnaturalenergysourceistransmitted,converted,andreleasedthroughthelivingtissuesandfoodchain[1].The
mostprimitiveformsofenergy,suchasoil,naturalgas,andcoal,areproducedandaccumulatedunderneaththeearthduetonatural
processesinthepastmillionsofyears.Thesenonrenewablefossilfuelresources,whichhavetremendousvalueforusnowandfor
ourfuturegenerations,areexpectedtobedepletedduetotheworldpopulationgrowthandindustrialdevelopment[1,2].Withthe
emergenceanddevelopmentofindustrialandagriculturalactivities,numerousproducts,includingplastics,textiles,fertilizers,and
productsfromsteelmanufacturingandpetrochemicalindustry,havebeengeneratedtomeetourdailyneeds.Aslargerandmore
industrialplantsarebuilt,obviouslymoreenergyisrequiredforoperation,processing,andtransportation[3].Theworldpopulation
isincreasingrapidly,especiallyinthedevelopingcountries,withanapproximately80millionmoreadditioneveryyear[4].People’s
lifestyleshavebeenchanginggradually,particularlyinthedevelopedcountries,andthedevelopingnationsarefollowingthetrend.
Energymakesworkandlifemoreconvenientandefficient.Therisingpopulationanddemandforconvenientlifestyleswillrequire
more goods and therefore more energy resources. Considering the imbalance between supply and demand due to depletion of
nonrenewable energy resources might eventually trigger an energy crisis, open and undercover conflicts from an international
perspectivehavealreadystartedtotakeplace.Therefore,renewableenergyexploitationandenergyefficiencyimprovementarecritical
themesforsustainableenergysupply,aswellasplayanessentialroleincontinuouslyprovidingadecentlivingstandardforhuman
beings [1]. In the years between 1973 and 2010, the global energy consumption grew by 186% and supply for industrial use
increasedby157%[2,5,6].Currently,theworldenergysourcesareprimarilycontributedbyfossilfuels,hydropower,nuclearenergy,
windenergy,solarenergy,andotherrenewables(seeFig.1).AndtheInternationalEnergyOutlook2016projectsremarkablegrowth
inworldwideenergyconsumptionindifferentregionsovertheperiodof2012–40(seeTable1).
TheWorldEnergyCouncil(WEC)andInternationalEnergyAgency(IEA)reportedthattheworldenergydemandin2020is
expectedtoriseby50%to80%fromthe1990sandthenumberisprojectedtoincreasebymorethanone-thirdbytheyear2035
onthebasisofthepresentlevel.Itshouldbenotedthatapproximately60%ofthegrowthindemandwillmainlycomefrom
China, India, and the Middle East [2,7,8]. The global energy demand from all sources is expected to expand, including oil
(13%), coal (17%), natural gas (48%), nuclear (66%), and renewables (77%) [9]. Global electricity demand as well is fore-
castedtoincreaseby70%bytheyear2030[10].Therenewableenergycontribution,includinghydropower,geothermal,and
solar, is expected to reach 30% of total electricity supply by 2035 [10]. However, thermal electricity generation using coal,
naturalgasandnuclearwillstillserveforpowergenerationaroundtheworld,andcoalwillcontinuetodominatehavingthe
largestshare[11].
Overthepasttwodecades,hundredsofmillionsofpeoplelivingindevelopingcountries,particularlyinChinaandIndia,
have gained access to modern energy services due to their quickly growing urbanization and economic development [3].
However,therewerestill1.3billionpeoplewhodidnothaveanyshareintheuseofelectricitygeneratedintheyear2010,and
approximately 2.6 billion people still relied on traditional biomass energy, such as wood and other forms of biomass, for
cooking and heating purposes [9,12]. Moreover, Global Energy Assessment (GEA) stated that about nine billion people are
projectedtorequireaffordableenergyservicesbytheyear2050[13].Therenewableenergyhasrecentlyexperiencedexponential
growthintheshareoftheenergymarkets;however,itstillaccountsforonlyasmallportionoftotalprimaryenergysupply,and
theircontributionisnotlikelytohaveenormousimpactsinthenearfuture.TheWEC’sOutlookReportin2013indicatedthat
development of the renewables not only faces demand challenges, but also significantly depends upon financial and legal
supportsfromgovernmentsindevelopingcountries[7].Infact,therenewableenergydevelopmentratehasbeenslowerthanit
waspredicted20yearsago[7].Acomparisonofglobalprimaryenergyconsumptionoverthepast10yearsissummarizedin
Fig.1.Thefindingsclearlyshowthatthemajorityofconsumptionwasintheformoffossilfuels,whileaslightdecline(0.61%)
observedfrom2005to2015.Renewablesonlysharedasmallfractionthatfluctuatedfrom12%to14%,butitseemstohave
goneupsteadily.
1.12.1.2 Fossil Fuel
Fossilfuel is aprimary energy resource that playsa criticalrole inourdaily activities, includingtransportation, manufacturing,
electricityproduction,coolingandheatingsystems,andmanyotheruses[14].Fossilfuelsareformedbynaturalprocesses,suchas
anaerobic decomposition of dead organisms, and the energy contained originates in ancient photosynthesis [15]. These fuels
FossilFuels 523
2005
Nuclear, 5.7% Solar, 1.0% Wind, 0.2% Other
Hydro, 6.0% renewables,
0.5%
Oil, 35.6%
Gas, 22.7%
Coal, 28.3%
2010
Nuclear, 5.1 %
Solar, 0.1% Wind, 0.6% Other
renewables,
Hydro, 6.4% 0.7%
Oil, 33.5%
Gas, 23.7%
Coal, 29.8%
2015
Nuclear, 4.4% Solar, 0.5% Wind, 1.4% Other
renewables,
Hydro, 6.8%
0.9%
Oil, 32.9%
Gas, 23.9%
Coal, 29.2%
Fig.1 Globalprimaryenergyconsumptioncomparisons.DatafromWorldEnergyCouncil.2016Surveyofworldenergyresources,London;2016.
Table1 Projectionoftheworld’sregionalenergyconsumption2012–40(EJ)
Regions 2012 2025 2040
OECDa 251 274 298
America 124 135 146
Europe 85 92 101
Asia 41 47 51
Non-OECD 322 413 533
Europe 54 58 61
Asia 186 260 340
MiddleEast 34 47 65
Africa 34 32 46
Americas 33 39 50
WorldTotal 591 710 860
aOrganizationforEconomicCooperationandDevelopmentmembercountries.Europe:Austria,Belgium,
CzechRepublic,Denmark,Estonia,Finland,France,Germany,Greece,Hungary,Iceland,Ireland,Italy,
Luxembourg,theNetherlands,Norway,Poland,Portugal,Slovakia,Slovenia,Spain,Sweden,Switzerland,
Turkey,UnitedKingdom.Othermembercountries:Australia,Canada,Chile,Israel,Japan,Mexico,New
Zealand,SouthKorea,UnitedStates.
Source:ModifiedafterWorldEnergyCouncil.2016Surveyofworldenergyresources,London;2016.
524 Fossil Fuels
Table2 Oil,naturalgas,andcoalreservesintopfivecountriesandtheirproductionsin2016
Oil Gas Coal
Countries Reserves Production Countries Reserves Production Countries Reserves Production
(Mt) (Mt) (tcm) (bcm) (Mt) (Mt)
Venezuela 47,000 124.1 Iran 33.5 202.4 UnitedStates 281,582 521.1
Saudi 36,600 285.7 Russian 32.3 579.4 China 244,010 2408.1
Arabia Federation
Canada 27,600 218.2 Qatar 24.3 181.2 Russian 160,364 275.4
Federation
Iran 21,800 216.4 Turkmenistan 17.5 66.8 Australia 144,818 427.6
Iraq 20,600 218.4 UnitedStates 8.7 749.2 India 94,769 401.3
Global 240,700 4382.4 Global 186.6 3551.6 Global 1,139,331 5223.4
Source:DatafromBP.Availablefrom:http://bp.com/statisticalreview[accessed21.10.17].
formed from the fossilized remains of dead plants [16] are formed by exposure to heat and pressure in the Earth's crust over
millionsofyears[17],andtheageoftheorganismsandhencetheresultingfuelsismanytimesolderthan650millionyears[18].
Fossilfuelscontainhighpercentagesofcarbonandincludecoal,oil,andnaturalgas.Someotherusedderivativescanbelistedas
kerosene and propane. Fossil fuels cover a range from nonvolatile materials with almost pure carbon (e.g., anthracite coal), to
volatilematerialswithlowcarbontohydrogenratios(e.g.,methane)toliquids(e.g.,petroleum).Inhydrocarbonfields,methane
canbefoundeitheralone,associatedwithoil,orinotherformsofmethane.
Fossil fuels are formed via natural processes continually; however, they are generally considered as nonrenewable resources
becausetheytakemillionsofyearstoform,andtheknownreservesarebeingdepletedmuchfasterthanthenewonesbeingmade
available[19,20].AsFig.1shows,theglobalprimaryenergyconsumptionin2015consistedofpetroleum32.9%,coal29.2%,and
natural gas 23.9%, amounting to an 86.0% share for nonrenewable fossil fuels in primary energy consumption in the world.
Nonfossilenergyconsumptionin2015includedhydroelectric6.8%,nuclear4.4%,wind1.4%,solar0.45%,andotherrenewables
amountingto0.89%[21].Andworldenergyconsumptionisgrowing.
As it is seen clearly, fossil fuels are closely linked to our lives; therefore, it is important to figure out their impacts on the
surrounding environment and other related resources [22]. The burning of fossil fuels produces around 21.3 billion tonnes of
carbondioxide(CO )peryear.Andnaturalprocessescanonlyabsorbpartofthisrelease,anditisestimatedthatonlyabouthalf
2
ofthisamountcanbeabsorbedbynaturalprocesses.Hence,thereisasurplusof10.65billiontonnesofCO ,whichisreleasedto
2
theatmosphereeveryyear[23].ItisnowacommonknowledgethatCO isagreenhousegas,whichincreasestheatmospheric
2
radiativeforcingduetoitsglobalwarmingpotentialandthereforecontributestoglobalwarming.Thereisaglobaltrendtoward
thegenerationofmorerenewableenergytohelpreduceglobalgreenhousegasemissionsincludingtheemissionsfromfossilfuels.
Also, the linkage between energy and water has become clearer recently [2,3,24]. The extraction and processing of fossil fuels
requirealargeamountofwaterinput,whichfrequentlyimpactsthewaterqualitynegatively[24].
Duetotheenvironmentalconcernsandothers,thecontributionoffossilfuelsisexpectedtodropwiththerapidgrowthof
clean and renewable energy sources. Fossil fuel reservoirs are not equally distributed around the world. In 2017, the British
Petroleum(BP)publishedreservesandproductionofoil,naturalgasandcoalfromthetopfivecountriesintheyear2016.Table2
showsthatreservesaremainlyconcentratedintheMiddleEast,NorthAmerica,RussianFederation,andAsia.About77%oftotal
coal production was exploited from the top five reserves, while only 50% and 24% of global natural gas and oil productions,
respectively.Furthermore,theIEA[22]predictedandpublishedtheworldpetroleumandotherliquidfuels,naturalgas,andcoal
productionbyOrganisationforEconomicCooperationandDevelopment(OECD)andnon-OECDcountriesovertheperiodfrom
2012to2040(Fig.2)[11].
1.12.1.3 HubbertPeak Theory
AmericangeophysicistM.KingHubbert,in1956,proposedthatfossilfuelproductioninagivenregionovertimewouldfollow
roughlyabell-shapedcurve,withoutprovidingapreciseformula.However,forestimatingfutureproductionusingpastobserved
discoveries, he later used the Hubbert curve (Fig. 3) – the derivative of the logistic curve (common S-shaped sigmoid curve)
[25,26]–whichisanapproximationoftheproductionrateofaresourceovertime.Heassumedthatafterfossilfuel(oil,coal,and
naturalgas)reservesarediscoveredandasmoreextractiontakesplace,productionfollowsapproximatelyanexponentialincrease.
Andatsomepointofextraction,eventuallyapeakoutputisreached,andproduction startstodeclineuntilitforms,thistime,
approximately an exponential decline. The Hubbert curve is roughly symmetrical and has a single peak, satisfying the above-
mentionedcharacteristics;andproductionreachesthepeakwhenabouthalfofthefossilfuelthatwillultimatelybeproducedhas
beenproduced.Providedanypastfossilfueldiscoveryandproductiondata,aHubbertcurvethatapproximatespastdiscoverydata
canbeconstructedandusedtoprovideestimatesforfutureproduction.Eventually,theapproximatetimeofpeakfuelproduction
andthetotalamountoffuelthatwouldultimatelybeproducedareestimatedthatway.
FossilFuels 525
25
OECD Non-OECD
20
y
a
3m/d 15 11.89
on 10 7.12 8.66
Milli
5
7.23 7.23 7.33
0
(A) 2012 2020 2040
7.0
OECD Non-OECD
6.0
5.0
3
m
4.0
n 3.85
o 2.76
Trilli 3.0 2.13
2.0
1.0 1.26 1.47 1.88
0.0
(B) 2012 2025 2040
10,000
OECD Non-OECD
8000
s
n
n to 6000 6115 6671 7099
o
Milli 4000
2000
2029 2174 7133
0
(C) 2012 2025 2040
Fig.2 Worldproductionof(A)petroleumandotherliquidfuels,(B)naturalgas,and(C)coalbyregionsovertheperiodfrom2012to2040.
OECD,OrganisationforEconomicCooperationandDevelopment.DatafromUnitedStatesEnergyInformationAdministration.Internationalenergy
outlook2016,U.S.DepartmentofEnergy,Washington,DC;2016.
0.25
0.20
0.15
0.10
0.05
0
−6 −4 −2 0 2 4 6
Fig.3 ThestandardHubbertcurve.Forapplications,thexandyscalesarereplacedbytimeandproductionscales.
526 Fossil Fuels
1.12.2 Oil
As mentioned earlier, just like natural gas, oil is formed by the anaerobic decomposition of organic matter including phyto-
plankton and zooplankton, which were settled in large quantities in deposition basins, such as a seabed or lakebed, over
geological time. This organic matter, after being mixed with mud, remained buried under increasing layers of sediment over
millionsofyears.Asaresult,theorganicmatterandmudmixturewasexposedtohighpressuresandtemperaturesovermillionsof
yearscausingtheorganicmattertochemicallychange,firstintokerogen(awaxymaterial,whichisfoundinoilshales),andthen,
withmoreexposuretofurtherheat,intoliquidandgaseoushydrocarbonsinaprocessknownascatagenesis.Throughoutallthese
processes,theenergydensityofhydrocarbonsmightincrease;however,theoriginoftheenergyisstilltheancientphotosynthesis.
Currently,theworld’sprimaryfuelsourcefortransportationisoil,whichalsoexistsinshaleandtarsands;however,mostoilis
pumpedoutofundergroundreservoirs.Oilisextracted,andthenitisprocessedinrefineriestocreatefueloil,gasoline,liquefied
petroleumgas,andotherproductslikefertilizers,pesticides,pharmaceuticals,andplastics.However,oilcausesseriousenviron-
mental problems and the heavy reliance on oil particularly for transportation makes it difficult to reduce its consumption.
Furthermore,theenvironmentaldegradationcausedbyextractionandoilspills,combustionofoilemitsfineparticulates,which
canleadtoserioushealthproblemsforhumans,andisalsoamajorsourceofgreenhousegasemissions.Aswekeepdepleting
conventional oil sources from underground reservoirs, unconventional sources, such as tar sands and oil shale, attract more
attention.Heaviercrudeoilsextractedfromsuchsourcesresultinmoreemissionsandenvironmentaldisturbancecomparedto
conventionaloilbecausetheirextractionisinvolvedintheuseofenergyintensivemethods.
1.12.2.1 Sources ofOil
Oil comes from both conventional and unconventional sources. The terms, conventional and unconventional sources, are
however not clearly defined in the literature and the definitions vary considerably. For instance, Hubbert limited his peak oil
prediction in 1956 to the crude oil producible by methods then in use. His later analyses included future improvements in
explorationandproduction[27];however,allhispeakoilanalysesexcludedtheoilfromoilsandsandoilshale.Wecangivea
2013study,asanexample,whichpredictedanearlypeak,excludedtheoil,suchasdeepwateroil,tightoil,andoilclosetothe
poles, all of which were defined as nonconventional sources [28]. This chapter provides commonly used definitions for con-
ventionalandunconventionaloilaspresentedbelow.
1.12.2.1.1 Conventional sources
Oilextractedonlandandoffshoreusingstandardtechniquesisdefinedasconventional.Andwithrespecttograde,thoughthe
exactdefinitionsofthegradesvarybasedonwheretheoilcomesfrom,thesesourcesarecategorizedaslight,medium,heavy,or
extraheavy.Lightoilflowsnaturallytothesurfaceandcansimplybeextractedbypumpingittothesurface.Heavyoilobviously
referstotheoilthatdoesnotfloweasilybecauseofitshigherdensity.Whileconventionaltechniquesarepartlyusedforproducing
thisheavyoil,typicallytheuseofunconventionalmethodsprovestoprovidebetterrecoveryrates[29].
1.12.2.1.2 Unconventional sources
Itdoesnotmeanthatitwillbesoforever;however,currentlythefollowingoilsourcesareconsideredunconventional.
(cid:129)
Oil sands: these are unconsolidated sandstone deposits containing large amounts of viscous crude bitumen or extra heavy
crudeoil.Theycanberecoveredbysurfaceminingoroilwellsusingsteaminjectionorothertechniques.Suchdeposits are
liquefiedbyblendingwithdiluents,upgrading,orheating;andthen,processedatanordinaryoilrefinery.Therecoveryofthese
depositsrequiresanadvancedtechnology,whichisdifferentfromaconventionaltechnologyandmoreefficientthanthatofoil
shale, for instance, due to the sandstone deposits’ producing oil much more easily compared to oil shale or marl. These
formationsarequiteoftencalled"tarsands,"suchasCanadiantarsands;however,thematerialexiststhereisactuallynottar,
ratheritisanextraheavyandviscousoilknownasbitumen[30].
(cid:129)
Oilshale:oilshaleisusedasacommontermforsedimentaryrock,suchasshaleormarl,whichcontainskerogenthatisyettobe
transformedintocrudeoilbythehighpressuresandtemperaturesduetodeepburial.Theseformationsareclosetothesurface;
therefore,theyaregenerallymined,crushed,andretorted,eventuallymanufacturingoil(synthetic)fromthekerogen[31].
(cid:129)
Tightoil:thisistheoilextractedviahydraulicfracturingfromlow-permeabilityrockdeposits,shaledeposits,andmanytimes
fromotherrocktypesaswell[32].Itshouldnotbeconfusedwithshaleoil,whichis,asmentionedabove,theoilmanufactured
fromthekerogencontainedinanoilshale.
(cid:129)
Coalliquefactionorgas-to-liquids(GTLs)product:thesearesynthesizedliquidhydrocarbonsfromtheconversionofcoalor
naturalgasbyanumberofprocesses,suchasFischer–Tropschprocess,Bergiusprocess,orKarrickprocess.Sasolcurrentlyhas
workingcommercialscalesyntheticoiltechnologiesbasedoncoal-to-liquid(CTL)andnaturalGTLtechnologies,producing
$4.40billioninrevenues.Shellhasalsoemployedtheseprocessestoconvertandrecyclewasteflaregasburntoffatoilwells
andrefineriesintousablesyntheticoil.However,forCTLconversion,ithasbeennotedthatcoalreservesmaynotbesufficient
tosupplyworld’sneedsforbothliquidfuelsandelectricpowergeneration[33].
(cid:129) Minor sources: these include thermal depolymerization, which could indefinitely be used to produce oil out of waste feed-
stocks,suchasagriculturalwaste,garbage,andsewage.Forinstance,LosAlamosLaboratory,UnitedStates,statedthathydrogen
FossilFuels 527
–potentiallyproducedusinghotfluidfromnuclearreactorstosplitwaterintohydrogenandoxygen–incombinationwith
sequesteredCO couldbeusedtoproducemethanol,whichcouldthenbeconvertedintogasoline[34].
2
1.12.2.2 Oil Reserves
Primary energy source levels are the carbon based fossil energy reserves in the ground. Flows or daily productions of such
sourcesareknownasproductionoffossilfuelsfromthesereserves.Whenwetalkaboutoilreserves,wespecificallymeanthe
amountofcrudeoil,whichcantechnicallyberecoveredinafinanciallyfeasiblemanneratthepresentpriceofoil[35].Thetotal
estimatedamountofoilinanoilreservoir,includingbothproducibleandnonproducibleoil,iscalledoil-in-place.Duetothe
limitationsofoilextractiontechnologiesatthetimeandreservoircharacteristics,notthewholebutonlyaportionofthisoilcan
be recovered and brought to the surface of the Earth. And this producible portion is considered as reserves. Oil resources
howeverincludealloilthatcantechnicallyberecoveredatanyprice,notonlyatthepresentprice.Therefore,asitisclearlyseen
and understood, unlike oil resources, oil reserves vary as a function of the price. Reserves for instance typically indicate the
reservesforapointofinterest,suchasasingleoilwell,asingleoilreservoir,asingleoilfield,asinglecountry,orthewhole
world.Theratioofreservestothetotalamountofoilinaspecificreservoiriscalledtherecoveryfactor.Thence,themethodof
oilrecoveryused,theoperationitself,andtherelevanttechnologicaldevelopmentsalltogetherdeterminetherecoveryfactorfor
agivenfield,forinstance[36].Mostearlyestimatesoftheoilfieldreservesaregenerallyconsideredconservativeandtendto
growwithtime(whichiscalledreservesgrowth)asafunctionofnewtechnologicaldevelopments[37].Fig.4showstheglobal
oilreservesinbillionbarrels(bbl)in2013.
Oil producing nations do not typically reveal their engineered reservoir data due to their national security concerns, and
instead,providemanipulateddataforpoliticalreasons[38,39].However,BPattheendof2016reported(seeTable3)thatthe
highestprovedoilreserves(includingnonconventionaloildeposits)arelocatedinVenezuela(17.6%ofglobalreserves),Saudi
Arabia(15.6%ofglobalreserves),Canada(10%ofglobalreserves),Iran(9.3%),andIraq(9.0%),withthehighestreserves-to-
production (R/P) ratios belonging to Venezuela and Canada, 341.1 and 105.1 years, respectively, and the global ratio of 50.6
years.OrganizationofthePetroleumExportingCountries(OPEC)dataattheendof2016showedsimilarreservenumbers[40].
301 bn bbl
267 bn bbl
110 bn bbl
30 bn bbl
0
Fig.4 Globalmapofoilreservesin2013.ReproducedfromWikipedia.Availablefrom:https://en.wikipedia.org/wiki/Oil_reserves[accessed21.10.17].
Table3 Provedoilreservesintopfivecountriesbetween1996and2016(reservelevelsareinthousandmillionbarrels)
Countries 1996 2006 2016 Shareoftotal(%) Reserves-to-production(R/P)ratio
Venezuela 72.7 87.3 300.9 17.6 341.1
SaudiArabia 261.4 264.3 266.5 15.6 59.0
Canada 48.9 179.4 171.5 10.0 105.1
Iran 92.6 138.4 158.4 9.3 94.1
Iraq 112.0 115.0 153.0 9.0 93.6
Totalworld 1148.8 1388.3 1706.7 100.0 50.6
Source:DatafromBP.Availablefrom:http://bp.com/statisticalreview[accessed21.10.17].
528 Fossil Fuels
1.12.2.2.1 Reserves of unconventional oil
Oil becomes less and less available every passing year. And this can only be substituted with production of liquid fuels from
unconventionalfuelsources,suchasoilsands,tightoil,shaleoil,ultra-heavyoils,biofueltechnologies,CTL,andGTLtechnol-
ogies [41]. That is why, International Energy Outlook (IEO) in its 2007 and later reports, in presenting world energy reserves,
productionandconsumption,usedtheword“Liquids”ratherthanthe“Oil”[42,43].Also,biofuelswasincludedinthe“Liquids”
sectioninsteadofinthe“Renewables”in2009[44].However,theinclusionofnaturalgasliquidsinthe“Liquids”sectionhasup
tocertainextentbeencriticizedasitisachemicalfeedstock(by-productofnaturalgas)andgenerallynotusedasatransportfuel
[45].
Asmentionedearlier,oilreserveestimatesarefunctionoftheoilprice;andtherefore,asunconventionalsourcesareincludedin
thepictureandnewtechniquesreducethecostofextraction,thereserveestimateswillvaryintime.Itisawellknownfactthatitis
more labor and resource intensive to produce the unconventional sources, which obviously require additional energy to refine
(i.e.,higherproductioncosts).Also,ona“well-to-tank”basis,approx.threetimesmoregreenhousegasemissionsareemittedper
bblequivalent[46,47].Theenergyandotherresources needed,andenvironmental effectsofextractingunconventional sources
havealwaysbeenhighprohibitingtheextractionofsuchsources;however,anumberofmajorunconventionalsourceshavebeen
broughttothetableforlarge-scaleproduction.TheoilsandsintheWesternCanadianSedimentaryBasin(seeFig.5)[48],theoil
shaleoftheGreenRiverFormationinColorado,Utah,andWyomingintheUnitedStates,andtheextraheavyoilintheOrinoco
BeltofVenezuela[49],canbegivenasexamplesofsuchefforts.Bitumenhasalsobeenextractedformanydecadesbycompanies,
such as Suncor and Syncrude; but with the support of new extraction technologies, production has tremendously increased in
recentyears[50].Itisestimatedthat,takentogether,theseresourceoccurrencesintheWesternHemisphere,areapprox.equalto
the identified reserves of conventional crude oil sources in the Middle East [51]. It is believed that the world's reserves of
unconventionaloilareseveraltimeslargerthanthoseofconventionaloil[52](seeFig.6).TheUSGeologicalSurvey,inOctober
2009,updatedVenezuela’sOrinocotarsandsrecoverablemeanvalueto513billionbbls(81.6billionm3),witha90%chanceof
beingwithintherangeof380–652billionbbls(103.7billionm3),makingthisareaasoneoftheworld'slargestrecoverableoil
fields[53].
Oilextractedfromunconventionalsourcescontainssulfurandheavymetals,whichareenergyintensivetoextractandcanleave
thesiteinsomecases[46,54].ThesamethingistrueformuchoftheundevelopedconventionaloilreservesintheMiddleEast,
whichisheavy,viscous,andcontaminatedwithsulfurandmetals[55].However,thesesourcesbecomemoreappealingfinancially
Fig.5 Syncrude'sMildredLakeminesiteandplantnearFortMcMurray,Alberta,Canada.Theyellowstructuresarethebasesofpyramidsmade
ofsulfur–noteconomicaltosellsoSyncrudestockpilesitinstead.Behindthepilesisthetailingspond,recognizedasthelargestdaminthe
world.Theextractionplantistotherightofthispictureandthemineistotheleft.ReproducedfromWikipedia.Availablefrom:https://en.
wikipedia.org/wiki/Peak_oil#cite_note-102[accessed21.10.17].
FossilFuels 529
Total world oil reserves
80%
Conventional oil
70%
Heavy oil
60% Extra heavy oil
Oil sands bitumen
50%
40%
30%
20%
10%
0%
Conventional Unconventional
Fig.6 Comparisonofconventionalandunconventionaloilreserves.ReproducedfromAlboudwarejH,FelixJ,TaylorS,etal.Highlightingheavy
oil.OilfieldRev2006;18(2):34–53.
150 North America 160
S & C America
Europe and Eurasia
Middle East
Africa 140
Asia Pacific
120 World
120
180
90
80
60
60
40
30
20
North S & C Europe Middle Africa Asia 0 86 91 96 01 06 11 16 0
America America and East Pacific
Eurasia
Fig.7 2016(left)andhistory(right)ofregionaloilreserves-to-production(R/P)ratios(years).ReproducedfromBP.Availablefrom:http://bp.
com/statisticalreview[accessed21.10.17].
whenoilpricesgohigh[56].Mackenzie[57]forecastedthattheworld'sextraoilsupplybytheearly2020swilllikelybecoming
fromunconventionaloilsources.
Theoilreservesweresuspectedtoberunningoutinthecomingdecades.However,withthehelpofadvancedtechnologies,
moreoilreserveshavebeendiscoveredandbecameviable;asaresult,theglobaloilreservesincreasedby60%withinpast20years
witha25%growthinoilproduction[7],nowhavingSouthandCentralAmericathehighest(120years)oilR/Pratiosratherthan
theMiddleEast(seeFig.7).Itispresentlyexpectedtoexpandfurtherasunconventionaloilsourcesmentionedabovearetaken
intoaccount.Weknowthatoilsandsaremixturecompoundsthatcontainclay,water,sand,andbitumen[58];andGosselinetal.
[195,59]indicatedthattheAlbertaoilsands(seeFig.5),forinstance,havegreatcompetitivenessinCanadathataccountedfor
approximately50%oftotalCanadianoilproductionin2009.Also,thereisnooilintheoilshale;however,itcontainsaunique
materialcalledkerogen,whichisaprecursorofcrudeoil[58].Theworldresourcesofoilshaleareestimatedaround730trillion
liters, which is reported to have four times greater than crude oil reserves currently [21]. Both oil sands and oil shale must be
refinedbeforetheycanworkasconventionalcrudeoil[60].Therefore,theynotonlyrepresentanincreasedoilreserve,butalsoan
530 Fossil Fuels
increasedenvironmentalburden.Themoretechnologiesemployedforextractionandprocessing,themoresevereistheimpacton
air,water,landandenergyresources.
1.12.2.3 Oil Production,Demand andTrade
Fig. 8 below shows the global distribution of oil producing nations in 2013 [61]. BP Energy Outlook 2017 [62] provided a
detailedreportforthecurrentandpast20year’soilproductiondataaswellastheprojectionsforthenext20years.Basedonthis
report,annualproductioninmilliontonnesofoilequivalent(Mtoe),oil,coal,andnaturalgasprovided85.4%ofprimaryenergy
productionin2015(32.4%þ29.2%þ23.9%,respectively).Currently,oilistheworld'slargestprimarysourceofenergy.
Table4indicatesthatglobaloilproductionin2015increasedby32.7%comparedtothatin1995,andisprojectedtoincrease
furtherinthenext20years(9.3%basedonthe2015productionfigures).ThemainincreasehasbeenandwillbeintheMiddle
EastandNorthAmerica(Canada,Mexico,andtheUnitedStates),whilethereisamajordeclineinoilproductioninEuropeand
almostasteadyproductioninAfricaandAsiaPacific.
Table5,ontheotherhand,showstheregionaloilproductionsin1995,2015,andprojectedoilproductionsin2035,aswellas
therelevantchangesinregionalproductions.Basedonthisreport,theMiddleEast,NorthAmerica,andtheCommonwealthof
IndependentStates(CIS)willcontinuetopreservetheirleadingsharesofglobaloilproductionwithfurtherproductionincreases
through2035,whiletheSouthandCentralAmericasustainingitssharewithincreasedproduction,andotherregionsobservinga
Barrels per day (bbl/day)
≥ 10,000,000
≥ 3,000,000
≥ 1,000,000
≥ 500,000
≥ 150,000
≥ 100,000
≥ 50,000
≥ 25,000
≥ 10,000
≥ 5000
≥ 1000
> 0
0 Countries by oil production in 2013
Fig.8 Globalmapofoilproducingcountriesin2013.ThemapisAliZifan’swork,whichwaspreparedusingdatafromCIAWorldFactbook.
ReproducedfromWikipedia.Availablefrom:https://en.wikipedia.org/wiki/Peak_oil#cite_note-102[accessed21.10.17].
Table4 Oilproductionbyregion(milliontonnesofoilequivalent)
Regions Years
1995 2000 2005 2010 2015 2020 2025 2030 2035
NorthAmerica 645.8 642.6 637.8 638.8 910.3 940.0 1007.5 995.9 1004.1
S&CAmerica 300.1 343.4 374.4 375.8 396.0 389.9 404.5 434.8 454.0
Europe 311.1 332.3 268.6 196.5 164.7 146.4 133.3 94.6 66.6
CommonwealthofIndependentStates(CIS) 358.3 396.2 580.3 662.8 682.0 692.7 708.3 716.2 730.2
MiddleEast 979.2 1151.1 1227.4 1220.7 1412.4 1508.0 1618.2 1727.6 1818.7
Africa 339.6 370.9 466.4 481.8 398.0 386.6 392.8 390.2 382.7
AsiaPacific 352.2 380.8 382.4 402.4 398.3 355.8 348.7 331.6 311.9
Total 3286.3 3617.4 3937.5 3978.8 4361.6 4419.5 4613.2 4690.9 4768.1
Source:DatafromBP.Availablefrom:http://bp.com/statisticalreview[accessed21.10.17].
