Chapter 15:Chapter 15:

Fossil Fuels and the EnvironmentFossil Fuels and the Environment

OverviewOverview Fossil FuelsFossil Fuels Crude Oil and Natural GasCrude Oil and Natural Gas CoalCoal Oil Shale and Tar StandsOil Shale and Tar Stands

Fossil FuelsFossil Fuels

Fossil fuels are forms of stored solar Fossil fuels are forms of stored solar energyenergy Plants convert solar energy to chemical Plants convert solar energy to chemical

energy through photosynthesisenergy through photosynthesis Oil, natural gas, and goalOil, natural gas, and goal

Formed from incompletely decomposed Formed from incompletely decomposed organic matter converted by chemical organic matter converted by chemical reactionsreactions

Provide 90% of energy consumedProvide 90% of energy consumed

Crude Oil and Natural GasCrude Oil and Natural Gas

Hypothesized that they are derived Hypothesized that they are derived from organic matter buried in from organic matter buried in depositional basinsdepositional basins Primarily found along plate boundariesPrimarily found along plate boundaries Exceptions to this include Texas, Gulf of Exceptions to this include Texas, Gulf of

Mexico and the North SeaMexico and the North Sea

Crude Oil and Natural GasCrude Oil and Natural Gas Source rockSource rock

Fine grained, organic-rich sedimentFine grained, organic-rich sediment At least 500 m depthAt least 500 m depth Subjected to increased heat and Subjected to increased heat and

pressurepressure Initiates the chemical transformationInitiates the chemical transformation

Elevated pressure causes sediment to Elevated pressure causes sediment to be compressedbe compressed

Initiates upward migration to lower-pressure Initiates upward migration to lower-pressure reservoir rockreservoir rock

Crude Oil and Crude Oil and Natural GasNatural Gas

Reservoir rockReservoir rock Coarser grained and Coarser grained and

relatively porousrelatively porous Ex: sandstone and Ex: sandstone and

porous limestoneporous limestone

TrapTrap Cap rock (often Cap rock (often

shale) blocks natural shale) blocks natural upward migration of upward migration of the oil and gasthe oil and gas

Often form in Often form in anticlines or faultsanticlines or faults

Petroleum ProductionPetroleum Production

Primary productionPrimary production Involves pumping oil from wellsInvolves pumping oil from wells Recovers only 25% of petroleum in Recovers only 25% of petroleum in

reservoirreservoir Enhanced recoveryEnhanced recovery

Increases the amount recovered to Increases the amount recovered to ~60%~60%

Steam, water, or chemicals injected into Steam, water, or chemicals injected into the reservoir to push oil towards wellsthe reservoir to push oil towards wells

Petroleum ProductionPetroleum Production Proven oil reserves Proven oil reserves

Portion of total resource that has Portion of total resource that has been identified and can be extracted been identified and can be extracted at a profitat a profit

Majority are located in Middle EastMajority are located in Middle East

Petroleum ProductionPetroleum Production

Consumption dominated by North Consumption dominated by North AmericaAmerica

Oil in the Twenty-First Oil in the Twenty-First CenturyCentury Proven oil reserves estimates Proven oil reserves estimates

Oil and natural gas will last only a few Oil and natural gas will last only a few decadesdecades

When will we reach peak production?When will we reach peak production? Likely to be between 2020–2050Likely to be between 2020–2050 Will have to adjust to potential changes Will have to adjust to potential changes

in lifestyle and economies in a post-in lifestyle and economies in a post-petroleum erapetroleum era

Oil in the Twenty-First Oil in the Twenty-First CenturyCentury Argument that we are head toward a Argument that we are head toward a

potential crisispotential crisis We are approaching the time when We are approaching the time when

approximately 50% of the total crude oil approximately 50% of the total crude oil available from traditional oil fields will available from traditional oil fields will have been consumedhave been consumed

Proven reserves (~1.2 trillion barrels)Proven reserves (~1.2 trillion barrels) World consumption is quickly using this upWorld consumption is quickly using this up

Oil in the Twenty-First Oil in the Twenty-First CenturyCentury

For every three barrels of oil consumed, For every three barrels of oil consumed, one is found one is found

Forecasts that predict a decline in Forecasts that predict a decline in production of oil suggest it will be in the production of oil suggest it will be in the next few decadesnext few decades

US production of oil as we know it will US production of oil as we know it will end by 2090end by 2090

World production as we know it by 2100World production as we know it by 2100

Oil in the Twenty-First Oil in the Twenty-First CenturyCentury Before shortages occur, need appropriate Before shortages occur, need appropriate

action to avoidaction to avoid Military confrontationMilitary confrontation Food shortagesFood shortages Social disruptionSocial disruption

Need to develop alternative energy Need to develop alternative energy sourcessources Solar energySolar energy Wind powerWind power Nuclear powerNuclear power

Natural GasNatural Gas Only begun to utilize this resourceOnly begun to utilize this resource

Pipelines technology is much betterPipelines technology is much better Recoverable gasRecoverable gas

Worldwide estimates = 60 yearsWorldwide estimates = 60 years US estimates = 30 yearsUS estimates = 30 years New supplies are being foundNew supplies are being found

Considered a clean fuelConsidered a clean fuel Produces fewer pollutants than burning Produces fewer pollutants than burning

oil or coaloil or coal Could be a transition fuel to alternative Could be a transition fuel to alternative

energyenergy

Coal-Bed MethaneCoal-Bed Methane

Coal formation produces methane Coal formation produces methane Stored within coalStored within coal Estimates = five-year supplyEstimates = five-year supply

Promising Energy SourcePromising Energy Source Environmental concernsEnvironmental concerns

1.1. Disposal of large volumes of salty Disposal of large volumes of salty waterwater

2.2. Migration of methane, which may Migration of methane, which may contaminate surrounding areascontaminate surrounding areas

Coal-Bed MethaneCoal-Bed Methane

Environmental benefitsEnvironmental benefits Produces much less carbon dioxide than Produces much less carbon dioxide than

coal or petroleumcoal or petroleum Reduces the amount of methane Reduces the amount of methane

released into the atmospherereleased into the atmosphere

Methane HydratesMethane Hydrates

Deposited beneath the seafloor at Deposited beneath the seafloor at depths >500mdepths >500m White, ice like compound White, ice like compound Made up of molecules of methane gas Made up of molecules of methane gas

“trapped” in ice“trapped” in ice Form as a result of microbial Form as a result of microbial

decomposition on the sea floor decomposition on the sea floor Also found on land in permafrostAlso found on land in permafrost

Methane HydratesMethane Hydrates

Deep, cold seawater provides high Deep, cold seawater provides high pressure and low temperaturespressure and low temperatures At lower pressure and warmer At lower pressure and warmer

temperatures, methane gas escapes as temperatures, methane gas escapes as bubbles from the ice trapbubbles from the ice trap

Potential energy source but currently Potential energy source but currently no way to mine or transport the gasno way to mine or transport the gas

Environmental Effects of Oil Environmental Effects of Oil and Natural Gasand Natural Gas Recovery, refining, and use of oil and Recovery, refining, and use of oil and

natural gas cause environmental natural gas cause environmental problemsproblems Air and water pollutionAir and water pollution Acid rainAcid rain Global warmingGlobal warming

RecoveryRecovery Environmental Environmental

Impacts of Impacts of Recovery on landRecovery on land Use of land to Use of land to

construct pads for construct pads for wells, pipelines, and wells, pipelines, and storage tanks and to storage tanks and to build a network of build a network of roadsroads

Pollution of surface Pollution of surface waters and waters and groundwatergroundwater

RecoveryRecovery

Accidental release of air pollutantsAccidental release of air pollutants Hydrocarbons Hydrocarbons Hydrogen sulfide Hydrogen sulfide

Land subsidence (sinking) as oil and gas Land subsidence (sinking) as oil and gas are withdrawnare withdrawn

Loss or disruption of and damage to Loss or disruption of and damage to fragile ecosystems, such as wetlandsfragile ecosystems, such as wetlands

RecoveryRecovery Environmental Environmental

impacts of recovery impacts of recovery in oceanin ocean Oil seepage into the Oil seepage into the

ocean ocean Release of drilling Release of drilling

muds containing muds containing heavy metals, such heavy metals, such as barium as barium

Aesthetic Aesthetic degradation from the degradation from the presence of offshore presence of offshore oil drilling platformsoil drilling platforms

RefiningRefining

Fractional Distillation at refineriesFractional Distillation at refineries Crude oil heated so its components can Crude oil heated so its components can

be separated and collectedbe separated and collected Accidental spills and slow leaksAccidental spills and slow leaks

Hydrocarbons released, polluting soil Hydrocarbons released, polluting soil and ground waterand ground water

Variety of chemicals used in the Variety of chemicals used in the industrial process which have the industrial process which have the potential to pollutepotential to pollute

Delivery and UseDelivery and Use

Transportation of Crude oilTransportation of Crude oil On land by pipelinesOn land by pipelines Across the ocean in tankersAcross the ocean in tankers Both have danger of oil spillBoth have danger of oil spill

Air pollution from combustion Air pollution from combustion Most serious impact associated with useMost serious impact associated with use Contributes to urban smogContributes to urban smog

CoalCoal Partially decomposed Partially decomposed

vegetation, vegetation, Slowly transformed in Slowly transformed in

solid, brittle solid, brittle carbonaceous rock if carbonaceous rock if buried in a sedimentary buried in a sedimentary environmentenvironment

Most abundant fossil Most abundant fossil fuelfuel

At current At current consumption rate consumption rate could last 250 yearscould last 250 years

CoalCoal Classified according to its energy Classified according to its energy

and sulfur contentand sulfur content Anthracite, Bituminous, Subbituminous, Anthracite, Bituminous, Subbituminous,

Lignite Lignite

Coal Mining and the Coal Mining and the EnvironmentEnvironment In USIn US

1000s of square miles disturbed by coal 1000s of square miles disturbed by coal miningmining

Only about half reclaimedOnly about half reclaimed ReclamationReclamation

Process of restoring and improving Process of restoring and improving disturbed land, often by reforming the disturbed land, often by reforming the surface and replanting vegetationsurface and replanting vegetation

Strip MiningStrip Mining

Surface process Surface process Overlying layers of soil and rock are Overlying layers of soil and rock are

stripped off to reach the coalstripped off to reach the coal >1/2 of the coal in US mined this way>1/2 of the coal in US mined this way

Acid mine drainageAcid mine drainage Side Effect of strip miningSide Effect of strip mining The drainage of acidic water from mine The drainage of acidic water from mine

sitessites Common in eastern US (abundant Common in eastern US (abundant

rainfall)rainfall)

Strip MiningStrip Mining

Acid mine drainage Acid mine drainage Occurs where Occurs where

surface water surface water infiltrates spoil infiltrates spoil banksbanks

Water reacts with Water reacts with sulfide minerals to sulfide minerals to produce sulfuric produce sulfuric acidacid

Acid pollutes Acid pollutes streams and streams and groundwatergroundwater

Strip MiningStrip Mining

In arid and semiarid regions the land In arid and semiarid regions the land more sensitive to mining activitiesmore sensitive to mining activities Exploration and road buildingExploration and road building Soils thin and water scarceSoils thin and water scarce

Makes reclamation more difficultMakes reclamation more difficult

Reclamation can minimize damageReclamation can minimize damage Laws vary by siteLaws vary by site

Mountaintop RemovalMountaintop Removal

Appalachian Mountain’s of West Appalachian Mountain’s of West VirginiaVirginia Strip-mining levels tops of mountains Strip-mining levels tops of mountains

and fills valleys with mining wasteand fills valleys with mining waste Flood hazard increases Flood hazard increases

Coal waste sludge dams formed by mine Coal waste sludge dams formed by mine wastewaste

Toxic waste water is stored Toxic waste water is stored Also produces large amounts of coal Also produces large amounts of coal

dustdust

Mountaintop Removal in West Mountaintop Removal in West VirginiaVirginia

Strip MiningStrip Mining

Surface Mining Control Act of 1977Surface Mining Control Act of 1977 US government required that mined US government required that mined

land is restored to support pre-mining land is restored to support pre-mining useuse

Prohibit mining on prime agricultural Prohibit mining on prime agricultural landland

Reclamation includesReclamation includes Disposing of wastesDisposing of wastes Contouring the landContouring the land Replanting vegetationReplanting vegetation

Underground MiningUnderground Mining Accounts for 40% of Accounts for 40% of

coal mined in the UScoal mined in the US Environmental Environmental

problems:problems: Acid mine drainage Acid mine drainage

and waste piles and waste piles pollute streamspollute streams

Land subsidence can Land subsidence can occur over minesoccur over mines

Coal fires in Coal fires in underground mines underground mines

Naturally caused Naturally caused Deliberately set Deliberately set

Transporting CoalTransporting Coal

Coal must get from mining areas to Coal must get from mining areas to large population centers large population centers Significant environmental issuesSignificant environmental issues

MethodsMethods Freight trainsFreight trains Slurring pipelinesSlurring pipelines

Require large amounts of waterRequire large amounts of water

The Future of CoalThe Future of Coal

Coal in USCoal in US 50% of electricity50% of electricity 25% of total energy consumed25% of total energy consumed

Comprises 90% of fossil fuel reservesComprises 90% of fossil fuel reserves Coal power plants emitCoal power plants emit

70% of sulfur dioxide70% of sulfur dioxide 30% of nitrogen oxides30% of nitrogen oxides 35% of carbon dioxide35% of carbon dioxide

The Future of CoalThe Future of Coal

Clean Air Amendments of 1990 Clean Air Amendments of 1990 mandate reducing coal emissionsmandate reducing coal emissions

Option for cleaner coal include:Option for cleaner coal include: Chemical and/or physical cleaning of coal Chemical and/or physical cleaning of coal

prior to combustionprior to combustion New boiler designs that permit lower temp New boiler designs that permit lower temp

of combustionof combustion Injection of material rich in calcium Injection of material rich in calcium

carbonate into the gases following burningcarbonate into the gases following burning Scrubbers - removes sulfur dioxidesScrubbers - removes sulfur dioxides

The Future of CoalThe Future of Coal

Options (continued)Options (continued) Conversion of coal at power plants into Conversion of coal at power plants into

gas before burninggas before burning Conversion of coal to oilConversion of coal to oil Consumer education about energy Consumer education about energy

conservation and efficiency to reduce conservation and efficiency to reduce the demand for energythe demand for energy

Development of zero emissions coal-Development of zero emissions coal-burning electric power plantsburning electric power plants

The Future of CoalThe Future of Coal

As oil and gas are used up, increased As oil and gas are used up, increased use of coal will have environmental use of coal will have environmental impactimpact More land strip minedMore land strip mined Air pollutantsAir pollutants Aesthetic degradationAesthetic degradation NoiseNoise DustDust Release of harmful or toxic trace elements Release of harmful or toxic trace elements

into the water, soil, and airinto the water, soil, and air

Allowance TradingAllowance Trading

EPA grants utility companies EPA grants utility companies tradable allowances for pollutingtradable allowances for polluting 1 allowance good for 1 ton of sulfur 1 allowance good for 1 ton of sulfur

dioxidedioxide Can be traded and sold by brokersCan be traded and sold by brokers

Idea is to reduced overall pollution Idea is to reduced overall pollution through economic market forcesthrough economic market forces

Environmentalists dislike thisEnvironmentalists dislike this They do not feel that companies should They do not feel that companies should

be permitted to buy their way out of be permitted to buy their way out of pollutingpolluting

Oil shaleOil shale

Fine grained sedimentary rock Fine grained sedimentary rock containing organic matter (kerogen)containing organic matter (kerogen) When heated to 500When heated to 500o o C oil shale yields C oil shale yields

oiloil Destructive distillationDestructive distillation Oil from shale called synfuelOil from shale called synfuel

Tar SandsTar Sands

Sedimentary rocks or sands Sedimentary rocks or sands impregnated with tar oil, asphalt, or impregnated with tar oil, asphalt, or bitumenbitumen Recovered by mining sands and Recovered by mining sands and

washing the oil out with hot waterwashing the oil out with hot water Found in Alberta, CanadaFound in Alberta, Canada

Strip minedStrip mined Similar problem as with shale, but Similar problem as with shale, but

greater volumegreater volume

Oil shaleOil shale

Recovery performed on both surface Recovery performed on both surface and subsurfaceand subsurface Disposal of waste a problem because Disposal of waste a problem because

shale must be retorted (crushed and shale must be retorted (crushed and heated)heated)

Volume of waste 20–30% greater than Volume of waste 20–30% greater than original volumeoriginal volume

Oil shale mining may developed as Oil shale mining may developed as oil prices riseoil prices rise